Lightweight water purification for peak performance in the outdoors! SteriPEN Adventurer Opti was built for the toughest mountains and rivers in the world. Backpacker Magazine gave it their Editor’s Choice Award in 2011 for changing the face of portable water purification. Recipient of a 2012 Desnivel Award … one of the 15 best new products. When camping, backpacking & hiking, if you won’t have access to the power grid for several days a time, the SteriPEN Adventurer Opti is the water purification system for you.