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The SteriPEN is a hand held, battery operated water purification device, which uses UV technology to make water safe for drinking. I've had this useful little gadget for a couple of years, which has given me plenty of time to test its benefits and discover its flaws.
** SteriPEN and UV technology **
Around a decade ago SteriPEN started using the century old technology of UV water purification to design a range of handheld water purification gadgets for the general public. Using UV light to sterilise water is widely done on a larger scale by water authorities to make tap water safe for entire cities, by many large brands to purify their bottled water and I've seen it in use at my local Oyster Fishery.
So, now for the science bit... According to the instructions from SteriPEN, UV purification works as the energy emitted by the light is absorbed by the cells of microbes. This prevents the enzymes in the cell from reading their DNA, and without intact DNA, microbes can't reproduce. As a result this destroys more than 99.9 percent of harmful bacteria, viruses and protozoan cysts such as giardia and cryptosporidia.
SteriPEN have had their products tested by various universities as well as the Water Quality Association. Everyone has given them the seal of approval so I have total confidence that the technology does what it claims. I remember watching a video on the SteriPEN website when this gadget first came out; it showed a guy using his SteriPEN to sterilise murky, brown water he had just scooped out of a bog(!), he then proceeded to drink the final result - this was all the convincing that I needed!
** Availability **
The SteriPEN is available in a range of different product variations. You can get the simple pen in a small or standard size, with or without a solar charging case or along with a selection of pre-filters (to remove large particles from water before purification). I own the SteriPEN Adventurer that you can see in the picture here, which comes with a solar charging case. This is the product combination I will be focussing on for the purpose of this review.
The Adventurer retails at around £110. I've never seen it in any outdoor shops, but you can get it from a variety of online stores, including Amazon, Outdoors Magic and Nomad. It's one of the most expensive bits of kit I own, and I was lucky enough to receive it as a leaving gift from work colleagues. I had been checking out the gadget online (whilst at work, naughty me - which probably explains why I received such a wonderful, yet random, gift) but I never considered purchasing it for myself because of the high price. I'm afraid I haven't changed my mind after using this, as I don't think I use it enough to make it pay for itself (I hope my old workmates don't read this!). However, I do think that if you find yourself in many situations where this would be useful then it is worth the initial spend.
** The SteriPEN **
The SteriPEN itself is small enough to fit in a pocket, and weighs just over 100g. It comes with a soft material case, but I rarely use this as I store it in the solar charging case. The pen is very sturdy so I wouldn't be concerned with just chucking it in a bag without any sort of case. The delicate glass bulb is covered by a strong plastic cap which snaps shut very firmly. All in all it seems very solidly built.
The SteriPEN Adventurer will purify up to a litre of water at a time. It utilises two CR123 batteries to do this (two rechargeable ones are provided with the product). You simply place the entire bulb into the water and press a button. Two sensors on the side of the plastic body mean that the UV light will not turn on until it is fully immersed in water. This is a safety precaution as the UV light is especially damaging to eyes.
There is a light on the side which changes from green to red and fast flashing to slow flashing depending on the programme set and the power available. I found it all quite complicated at the beginning. I'd recommend carrying the instructions with you on the first outing with this. Basically 10 seconds after pressing the button, the SteriPEN is ready to use. Pressing the button once will purify up to 1 litre of water, whilst pressing it twice will purify up to half a litre. You simply hold the pen in the water, swirling it around slightly until the bulb goes off and the water is ready to drink - simple! It takes 60 seconds to do 1 litre of water, so it's not too much of a hassle.
I usually take Sigg bottles away with me but I had to buy a wide mouthed Nalgene bottle instead, as the pen won't work in narrow necked bottles. This can be a bit of a pain if you're not very good at drinking out of wide necked bottles, like me, and end up spilling the contents all down your front instead!
** The solar charging case **
The solar charging case was a real disappointment. The instructions state it will take five days to charge a set of batteries in normal light conditions. At first I thought that must be a printing error, but it does in fact take forever. So long in fact, that after a week of leaving this out in the sun I gave up altogether. There is a light on the side of the solar charging case that tells you when the rechargeable batteries inside are fully charged and ready to be put back into the pen. The light never went off so I had to resort to mains power to recharge the batteries.
** Using mains power **
The SteriPEN Adventurer is not supplied with a mains adapter, so you have to purchase one yourself. Furthermore the mains adapter needed is about five times heavier than, and as bulky as, the entire product - case and all. Once plugged in it takes around 3 hours to recharge the batteries fully. I always have two sets of batteries with me so I can use the pen even when the batteries are recharging.
** The batteries **
So onto the batteries... along with the solar charger I discovered these are not quite as good as promised. One charge should power the SteriPEN for 40 to 50 treatments, but in my experience it only lasts for 5 - 6 treatments. This is using both the batteries supplied and ones purchased separately. It's enough to get one or two people through a day of sterile water before an overnight charge is needed so it isn't too much of an issue as long as your accommodation has a reliable night time mains power source.
The only issue occurs when you have no access to mains power, which let's face it is a very likely scenario for most people using this device whilst camping or trekking, or living in remote conditions in developing countries. In this situation the only option is to bring along disposable batteries and use those instead. I've tried this myself and find a set of disposable batteries (non-alkaline) last at least a fortnight (so that's around 40-50 1 litre treatments).
** The overall effect **
When water is purified in this way it does not affect the taste, smell or pH of the water. This is a real plus as anyone who has had to drink water purified with chemical tablets will know, it is not a pleasant experience. Before I took my SteriPEN away with me I tested it on a glass of tap water at home. I actually found that it improved the taste - don't ask me how (and perhaps it was psychological) - but the water definitely tasted 'purer' somehow.
** Usefulness **
I think this is a fantastic idea but it's not going to be useful for everyone. I take this with me on most overseas trips, but have not once used it in the UK. I'll admit to being a total cheapskate, and if I have the opportunity to save even a couple of pounds I will do. That's why I like to take this away with me to places where I know the tap water isn't safe to drink, but bottled water comes at a price. Friends think I'm a bit strange at first, sitting there painstakingly purifying a row of bottles of tap water in my hotel room - but before long they're all asking me if they can use it too.
I can see how it would be great to have a SteriPEN in other situations such as if you're hiking somewhere for the day and need to fill up your bottles from a stream, or you're camping somewhere with dubious drinking water available. However, since I've had my SteriPEN I've not been in those situations very much and so I've had limited opportunity to use it. An access to a power supply or lots of back up batteries is a must with this, and that's not always available or practical in these situations either. What at first seems like a lightweight, space saving water purification system can quickly turn into a heavy, bulky problem when many spare batteries are needed. I have to admit my small bottle of Puri-tabs are always more favourable when I know I have to carry everything around on my back.
SteriPEN have lots of creative suggestions for using one of these, for example as part of an emergency kit in case of natural disaster. Personally I'm not sure how many people could afford, or would want to buy one of these just in case they need it one day. I'd only recommend this for a serious outdoors enthusiast.
** Other things worth noting **
* The battery compartment on the end of the pen is removable only with the aid of a coin (or something of a similar shape and strength) so you'll need to have one handy at all times.
* The battery compartment has a rubber seal - but is not guaranteed watertight, so don't submerge the whole pen.
* The SteriPEN will not purify any water trapped in the ridges around the mouth of the bottle, so wipe any droplets off prior to drinking.
* The lamp bulb will only last up to 3000 litres before it needs replacing (and replacement bulbs cost nearly half as much as the SteriPEN itself!)
** Recommendations **
Overall I think this is a wonderful idea for a product, and faster and tastier than using filters and sterilising tablets any day. I wholeheartedly recommend the SteriPEN but would advise steering clear of the solar charging case and mains power adaptor. With some decent brand disposable batteries and a lot of opportunities for use, I'd say it offers value for money and is a worthwhile investment.
Thanks for taking the time to read my review; I hope you found it useful :)
This review is also posted on Ciao under my username sbeach000
Steripen / Water sterilising pen, using Uv technology. Ideal for purifying water when travelling/backpacking.