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SteriPEN Water Purifier Review – 5 Models

Last Modified: 04/19/2025


In this SteriPEN Water Purifier review, I present 5 UV water purifiers from the SteriPen brand. As the name suggests, they all work on UV (ultra-violet) light effects on bacteria and viruses. They are extraordinary effective tools for cleaning water for drinking.

UV water purifiers are one of several tools and methods you can use to get clean water. See more in my recent review of 5 best ways to purify water for drinking. These tools are typically very handy and suitable for backpackers, hikers, mountain climbers, and general travelers. 

The list includes:

  • SteriPen Freedom UV water purifier.
  • SteriPEN Emergency water purifier.
  • SteriPEN Ultra water purifier.
  • SteriPEN Classic 3 Bundle water purifier.
  • SteriPen Adventurer Opti handheld UV water purifier.

See them presented below.


1. SteriPEN Freedom Water Purifier

SteriPEN Freedom Water Purifier package.
SteriPEN Freedom Water Purifier package.

This is an ultralight and compact tool with only 2.6 oz (74 g), with integrated rechargeable batteries, and very easy to use.

According to its specifications, this tool destroys over 99.9% of bacteria and cysts, including Giardia and Cryptosporidium, as well as viruses.

As the name UV suggests, humans cannot see this light, but the indication of the tool working is a visible LED. You simply put it into the water and stir until the LED shuts off.

This means that the necessary dose of UV light has been applied to the water and destroyed all living organisms there. The light acts on their DNA making them harmless. The same method and technology is, in fact, used in hospitals and in other facilities.

Freedom Water Purifier in action.
Freedom Water Purifier in action.
  • Capacity: 16 oz (454 g) in 96 seconds.
  • Battery: internal, rechargeable.

You can recharge it through a computer, AC adapter, or through a compatible solar charger. The package with the solar charger is presently around $78 and it is available at Amazon. The tool is designed to operate only if enough power is left in the battery to fully clean the water.  So you are free of a risk of inadequate treatment.

Best use of this tool is in combination with some water filter, this in case that the water contains some particulates and solids which would prevent a full treatment.  For a water without dirt, you do not need it.

Where to buy

  • You will find it on Amazon.

Pros

  • Extraordinary handy.
  • Simple to use.
  • Very reasonable price.
  • A lot of positive reports from users. But…

Cons

  • Somebody was complaining about the battery, it did not hold the charge. The same was with yet another customer whose battery failed even after he received the new tool.

2. SteriPEN Emergency Water Purifier

SteriPen Emergency Water Purifier.
SteriPen Emergency Water Purifier.

All properties of the Emergency Purifier with respect to its effects on viruses and bacteria are completely the same as in the Freedom model described above. The UV physics of this model works in the same manner. There are only some technical differences.

This is a heavier model as compared to the Freedom Purifier, but still very compact, user-friendly, and easy to use.

You use this model in the same way, dip it into the water and stir. It will clean 16 oz (454 g) of water in less than a minute. So it is a bit more effective than the Freedom model. One set of batteries will provide you 200 water treatments, this is very efficient in every sense.

The remark about the necessity to have water without solids and debris holds here as well.

  • Capacity: it purifies 1 liter of water in 90 seconds.
  • Battery: 4 AA lithium (not included). Do not use alkaline batteries with this model.
  • Weight: 5.7 oz (162 g).

Place to buy

  • Check at Amazon.com.

Pros

  • Completely the same as for the Freedom model.

Cons

  • One customer was complaining about batteries, they lasted for 10 treatments only. But batteries are not the part of the package.

3. SteriPEN Ultra Water Purifier

SteriPEN Ultra Water Purifier.
SteriPEN Ultra Water Purifier.

This tool works on the same principles as those presented above, and you use it in the same manner. It comes with an integrated rechargeable battery that you can charge similar to the Freedom model, through your computer, solar panel, or adapter.

The package also included a USB cable. Fully charged Ultra can clean up to 50 liters of water.

You put the light tube in the water and stir. When the smiling face appears on the gadget, your water is ready.

  • Capacity: 1 liter in 90 seconds; 16 oz (454 g) in less than a minute.
  • 8000 treatments lamp.
  • Battery: internal, rechargeable.
  • Weight: 5 oz (140 g).

Place to buy

  • Check at Amazon.
  • Check at REI.
  • Check at Walmart.

Pros

  • Good users’ experience.
  • Efficient.
  • Integrated battery.

Cons

  • Expensive.

4. SteriPEN Classic 3 Bundle Water Purifier

SteriPEN Classic 3 Bundle Water Purifier.
SteriPEN Classic 3 Bundle Water Purifier.

The same UV technology, with an addition of prefilter which is included in the package. The role of the prefilter is to remove solids and particulates which otherwise could prevent a full treatment of water. The gadget has an indicator for 16 oz (454 g) or 32 oz (907 g), so this is the amount of water you can clean at one go.

A few technical specifications:

  • Capacity: 32 oz (907 g) in 90 seconds.
  • 8000 treatments lamp.
  • Battery:
    – 4 AA alkaline, not included; 50 liters of clean water with one set.
    – with lithium batteries, not included, 150 liters with one set.
  • Weight: 2.9 oz (82 g) but without batteries.

Place to buy

  • Check at Amazon.com.
  • Check at REI.

5. SteriPen Adventurer Opti Handheld UV Water Purifier

SteriPEN Adventurer Opti Mini Pack Water Purifier.
SteriPEN Adventurer Opti Mini Pack Water Purifier.

This is a Backpacker Magazine’s 2011 Editors Choice Award winner. The tool is useful for backpackers, international travelers, and campers.

Adventurer Opti includes an optical water sensor and temperature sensor aimed at ensuring that it works at optimal performance and that its internal components remain completely functional. The bulb which indicates purification serves also as an emergency light source.

Technical specifications

  • Capacity: 32 oz (907 g) in 90 seconds.
  • 8000 treatments per lamp.
  • 2 batteries CR123, included.
  • Weight: 3.8 oz (108 g) but this without batteries.

Place to buy

  • Check at Amazon.
  • Check at Walmart.

Here is a video from SteriPen about their Adventurer Opti Mini Pack Water Purifier:

I give a video for one model only, there are no essential differences between them so there is no need to add videos for all models given above.


Summary

To summarize this SteriPEN Water Purifier review, as you have noticed for each of the tools presented above there are complaints about their reliability. So I would say, having an extra package of some chemical treatment pills is strongly advised if you go to areas where water quality is a truly serious issue. For me going to the Alps, this is definitely not the case.

You may be surprised to see that I give the highest rank 9.5/10 to the number 4 above, the Classic Purifier. The reasons for that are a balance of the price, weight, the type of the battery, and the fact that it includes a prefilter as well, and it works with 2 types of batteries. I do not believe in integrated rechargeable batteries; they lose their features quickly and you are left without the water purifier tool.

Another question is: can you really be sure that you will not get any virus or bacteria when using some of these tools? Well, I am not in a position to give a qualified answer to this. I can only be sure if I use a properly boiled water, see my text about this.

Though, these UV water purifiers are so popular and widely used, that I can only hope it is true what producers of these tools claim. But I do believe they are good enough for my adventures in the Alps or in any other mountains.

If these tools are not what you want, please see the MSR Guardian Purifier which is able to remove even viruses.

Thank you for reading, I shall be happy to have some comments from you in the comment box below. Have a nice day.

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Mountains for Everybody site is reader-supported. This means that some of the links in the text are affiliate links, and when you buy products through our links we may earn some small commission to keep running the site. Filed Under: Water filters & purifiers Tagged With: steripen adventurer opti handheld uv water purifier, steripen classic 3 water purifier, steripen emergency handheld uv water purifier, SteriPEN Emergency Water Purifier, steripen freedom uv water purifier, SteriPEN Freedom Water Purifier, SteriPEN Ultra Water Purifier, uv water purifiers, water purifiers

Comments

  1. Andy says

    06/18/2022 at

    Your information is easy to understand and the clear differences between the very similar products is fantastic. The power sources and charging requirements was a defining factor based on my intended use in the field. Rechargable is a NO GO. These products are all designed to make a volume of water safe to drink without BOILING. The convenience and timeline is not comparable on any level as no one can drink boiling water. Life Straw doesn’t offer the same level of purity so again a NO GO. Thank you making this information available and pointing out everyone should have tablets on hand for back up safety. Redundancy is a safety plan in action.

    Reply
    • Jovo says

      06/18/2022 at

      Many thanks Andy, great to hear from you, and I am sure your thoughts will be appreciated by my readers.

  2. Tom Banton says

    01/19/2022 at

    Great Read and easy to follow the steps. I am looking for a great water purifier with no high maintenance and high ticket products. I will provide the result after detailed review

    Reply
  3. Manik Miah says

    09/01/2021 at

    Hi,

    I’m a reader of your awesome website https://mountainsforeverybody.com/steripen-water-purifier-review. Your website contains lots of content about home improvement, which are awesome and helpful.

    I’m writing to you because I’d love to contribute a guest post on your awesome website about the home improvement that I think will be helpful for your readers who love to do DIY projects. My article will help your readers to fix their home improvement small issues and tasks.

    I’ll make sure the piece overflows with information that can’t be found anywhere else. I hope my content will help your readers to get new ideas and tips.

    Cheers,

    Reply
    • Jovo says

      09/01/2021 at

      Hi, I am convinced that my readers do not come here to read bout home improvement.

  4. water softener says

    05/05/2020 at

    You pick up the best filtration system for your households. You can easily use and purified water without any worries. As a cause, you must use soft water.

    Reply
    • Jovo says

      05/05/2020 at

      Thank you James, great to hear from you. In fact, this is about outdoor purifiers.

  5. David says

    04/03/2019 at

    Thank for sharing those reviews and videos. I would like to get the SteriPEN Water Purifier. The UV filters are really great, this system is very useful in water treatments plants to avoid the chlorine.

    Reply
    • Jovo says

      04/03/2019 at

      Hi David, just follow the links in the text and you can order one. But I am not sure what you mean by chlorine, these purifiers are not designed for that.

  6. Alexa Bartel says

    02/10/2018 at

    Interesting idea for sure, but is there any point to getting one of these when you could just get a LifeStraw instead? With the LifeStraw you don’t even have to wait a minute for it to purify the water you can just start drinking it immediately. And it doesn’t require any electricity.

    Reply
    • Jovo says

      02/10/2018 at

      Hi Alexa, LifeStraw and LifeStraw Steel are great tools and my reviews abut them are very positive. But see some Cons in the text. Most importantly, those are filters and not purifiers. If you want a purifier and filter together check this Pure2Go which I am using now, or this more expensive MSR Guardian.

      Back to SteryPEN, this thing is also a purifier (sort of), it makes the micro-organisms harmless.

  7. James says

    02/08/2016 at

    Wow, that’s really cool! I didn’t realize these existed! That’s such an easy and affordable way to purify water!
    I like the way you’ve reviewed 5 similar products in one page, to make the differences between each of them clear to the readers.
    You clearly know what you’re talking about when it comes to this mountaineering technology, so i would be happy to trust your reviews!
    Nice article, thanks!

    Reply
    • Jovo says

      02/08/2016 at

      Hi James, thanks for dropping buy. Yes, these tools are nowadays widely available and many people are using them. As you realize they are really handy and one can always have them in hand luggage in traveling as well.

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