There are a lot of different water bottle and hydration bag options out there, but when weight and space are an issue out on the trail, HydraPak rises above the rest with ultra-light, durable, and collapsible water storage containers that won’t add dead weight or bulk to your pack. The Stash (in 1 liter or 750 ml sizes) is the perfect go-to bottle for staying hydrated on everyday adventures and longer treks into the mountains. These bottles are 50% lighter than solid water bottles, are super strong, hold their shape well when full, and collapse down nearly to the size of a hockey puck when drained. And they come in several bright colors (green, orange, or blue) or grey. Pick one up at REI. MSRP: $20-$25. Hydrapak.com. // (Wil Wheaton)