REASONS TO BUY
Lightweight
Rechargeable
Waterproof
Removes viruses and other pathogens
REASONS TO AVOID
Finicky battery life
Unreliable
Small treatment capacity
SteriPEN Ultra Review
A UV purification system that eliminates the threat of viruses and other pathogens
SteriPEN Ultra
Credit: SteriPEN
Our Verdict
The Ultra SteriPEN is a unique, rechargeable purification system that utilizes UV light. The wavelengths emitted decimate the DNA in these organisms, not allowing them to reproduce. While it does seem a little like magic, pressing a button and waving a wand, this unit has a few shortfalls. While we appreciate its lighter weight, slim profile, and fast treatment time, we wouldn't usually reach for this filter simply because of its lack of reliability due to its battery use. This is an excellent option for international travel or for sitting by the beach at your favorite resort in Mexico.
Compare to Similar Products
 This Product
SteriPEN Ultra | |||||
|---|---|---|---|---|---|
| Awards |  Best Overall Filter for Personal Use |  Best Collapsible Bottle Filter | Best Overall Filter for Group Use |  Best Bang for the Buck | |
| Price | $127.00 at Amazon Compare at 2 sellers | $43.95 at REI Compare at 2 sellers | $55.00 at REI Compare at 3 sellers | $134.95 at REI Compare at 3 sellers | $12.96 at Amazon Compare at 2 sellers |
Overall Score  |
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| Star Rating | |||||
| Bottom Line | A rechargeable UV purification system that is great for international travel | A solid option for personal filtration usage during fast and light backcountry missions | Our favorite collapsible soft bottle filter, thanks to a durable design that's consistent and easy to use | A low maintenance, easy-to-use gravity filter that works well for everybody on the trail | The best chemical treatment option that will kill all pathogens when given enough time |
| Rating Categories | SteriPEN Ultra | LifeStraw Peak Squeeze | Hydrapak Flux 1.5L | Platypus GravityWorks | Aquamira Water Trea... |
| Water Quality (20%) | |||||
| Durability & Maintenance (20%) | |||||
| Treatment Time (15%) | |||||
| Weight & Packability (15%) | |||||
| Ease of Set Up (15%) | |||||
| Ease of Filtration (15%) | |||||
| Specifications | SteriPEN Ultra | LifeStraw Peak Squeeze | Hydrapak Flux 1.5L | Platypus GravityWorks | Aquamira Water Trea... |
| Measured Weight (entire kit) | 6.7 oz | 3.8 oz | 5.0 oz | 11.5 oz | 3.0 oz |
| Removes Particulates (sediment, microplastics) | No | Yes | Yes | Yes | No |
| Effective Against Viruses | Yes | No | No | No | Yes |
| Effective Against Chemicals | No | No | No | No | No |
| Effective Against Heavy Metals | No | No | No | No | No |
| Effective Against Bacteria | Yes | Yes | Yes | Yes | Yes |
| Effective Against Protozoa (Giardia, Cryptosporidium) | Yes | Yes | Yes | Yes | Yes |
| Type of Filter/Purifier | UV treatment | Squeeze | Squeeze, in-line, on-the-go | Gravity filter | Chemical treatment |
| Filter Media or Active Ingredient | UV light | Hollow-core membrane microfilter | Hollow fiber | Hollow fiber | Chlorine dioxide |
| Filter Pore Size (Advertised) | N/A | 0.2 microns | 0.2 micron | 0.2 microns | N/A |
| Number of Liters/Gallons per Lifetime (Advertised) | 8,000 L / 2,113 gal (per bulb), 50 L / 13 gal (per charge) | 2,000 L / 500 gal | 1,500 L / 396 gal | 1,500 L / 396 gal | 114 L / 30 gal (per package) |
Our Analysis and Test Results
This UV light purification system requires a power source and water to purify. It can immobilize bacteria, protozoa, and viruses with a simple whirl of the wand, just like magic. While we appreciate this technology, we question its reliability. It has a short battery life and has a reputation for not working at inopportune moments.
A look at what comes with the SteriPEN Ultra.
Credit: Amber King
Water Quality
Like magic, you touch a button, swirl, and voila…clean water free of bacteria, protozoa, and viruses. The UV light sends out intense wavelengths that decimate these pathogens' DNA so they cannot reproduce. That means that even if they enter your system, it supposedly won't cause you any harm.
The SteriPEN Ultra uses ultraviolet light to get rid of harmful microorganisms.
Credit: Jen Reynolds
Since this isn't a filtration system, it does not filter out particulates and sediment. If you plan on traveling where the water is full of sediment, consider a filtration system instead. However, if you know that clear sources are what you'll primarily encounter, this unit should work like a charm.
Durability & Maintenance
This system supposedly can filter up to 50 liters per charge, though we noticed our battery running low before this claim, getting about half that, especially in colder weather. The company website says that one bulb can purify up to 8000 liters, but we don't know if this is true.
SteriPEN offers both rechargeable and battery-powered options. Depending on what you prefer, you should get the appropriate option. One of the most significant issues with this filter is reliability. We've experienced the SteriPEN glitching out on longer runs, leaving us without a water filtration system. If it's freezing, the battery will drain quickly. We also noticed that after several uses, the battery charge does not remain as well-boosted as it does at the beginning.
As a result of this lack of reliability, we can't wholeheartedly recommend it for extended backpacking trips. It's a good option for getting back to a power source for the plugin. Even if you bring along your favorite portable solar charger, you could get skunked if there's no sun. Even then, with a full charge, we experienced the sad face for no reason, which left us frustrated and without clean water. Luckily, we had a chemical treatment backup. Like everything electrical, it's not the most reliable in the backcountry and more suited for situations that won't leave you wondering if you'll survive.
Make sure you have access to a power source or you might find yourself without a purification system.
Credit: Amber King
Treatment Time
This unit counts down your purification time. It takes 90 seconds and some swirling to purify one liter of water. There is also the option to do a half-liter, which takes half the time.
The Ultra has simple directions on the unit, push the button once to treat 1 liter and twice to treat half a liter.
Credit: Jen Reynolds
Weight & Packability
The SteriPEN Ultra is a meager 6.65 ounces, including its squishy carry case. Of the SteriPEN models, it's the heaviest, but it's much lighter than pump filters that treat viruses. The narrow profile fits nicely into a backpacking pack or even a running pack. It's a little large for ultralightweight missions that might go for 20+ miles, but it works just fine for a trail run where you need water on the go.
Relative weight with the case.
Credit: Amber King
A look at relative size and profile.
Credit: Amber King
Ease of Set Up
The Ultra is very simple to use. Turn it on and place it in your bottle. Water retrieval depends on your storage container. If you are removing sediment from a water source, pre-filter your water or consider a filter instead.
Ease of Treatment
Treatment is also easy. Wait for 90 seconds per liter of purified water. Swirl it around. When you see the smiley face, your water is ready to drink! If you see a frowny face, it means your battery isn't working or something is wrong.
The Ultra takes 48 seconds to purify half a liter, which actually feels like a long time when you're standing there stirring the water around.
Credit: Jen Reynolds
Should You Buy the SteriPEN Ultra?
No doubt about it, the SteriPEN Ultra is pricy. Given that it's not super reliable, even though it does remove viruses and other harmful bacteria, it's not our first recommendation for most backcountry enthusiasts. However, if you like the idea and you'll be around power consistently, it is quite convenient, fast, and easy to use.
The smiley face on the Ultra makes tester Jessica Haist smile.
Credit: Jen Reynolds
What Other Backpacking Water Filters Should You Consider?
The Ultra does best for international travel or super short trips into the backcountry when it's not cold. This UV filter eliminates everything, including viruses, but its short battery life and inability to treat large amounts of water do limit its use. If you're interested in another lightweight option that's much more affordable and easy to use, check out the original Lifestraw. And if you don't mind filtration options that are lightweight and reliable, check out options like the LifeStraw Peak Squeeze and Katadyn BeFree 0.6L.
—Amber King
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