This nifty little system is similar to so many of those brilliant ideas out there, it's a simple product that works well, and it turns the hydration market on it's head. Now you don't need to buy a costly bladder and hydration pack to be able to drink on the move, just use the Convertube and one of the four adaptors on the bottle in your backpack. The sizes of the four adaptors that come in the pack: Sigg (42mm), Nalgene (63mm), Evian (24mm) and the standard PET (28mm). The tube itself is 94cm long, so you won't have any issues getting it to reach from the depths of your backpack through to your mouth. The inner tube length (the one that goes into the bottle) is 35cm long, so you won't have any issues getting to the water at the bottom of even the longer bottles. It also comes with a smart Helixâ„¢ bite valve (so you won't be spraying your face with water unnecessarily or sucking until your face turns blue) and it has the Dirt Shieldâ„¢ tech, so it will keep your water or juice clean from any outside grit or dust.