SteriPen Ultralight UV

The SteriPen Ultralight UV is the smallest and lightest UV water purifier in the SteriPen range, at just 76 g roughly half the weight of the Ultra model. It's USB rechargeable and, according to the manufacturer, destroys 99.99% of viruses, bacteria, and protozoa — including Giardia and Cryptosporidium — in 90 seconds per litre. Like other SteriPen UV purifiers, it skips the display and replaceable cartridge found on some water-treatment devices; the lamp is sealed and rated for 8,000 activations, after which the whole unit is replaced. The compact size and low weight make the Ultralight a straightforward pick for hikers who want the fewest possible grams in the pack and don't need a display or the Ultra's larger battery capacity. It requires clear, non-turbid water and a bottle with a mouth diameter of at least 38 mm, ruling out narrow-mouth sport bottles. As with other UV methods, this is disinfection rather than filtration — it does nothing for sediment, taste, or chemicals. It suits quick treatment of clear mountain water sources on trek where minimizing weight is the priority.