The hydration bladder is to be placed in a special PFD pocket on the back. The tubing passes also through special fasteners of the PFD in order to be conveniently close to your mouth.
The advantages are obvious: Sometimes you can’t afford to drop the paddle, to open a water bottle with both hands and drink. It can happen in high winds or while fighting waves and currents. In an extreme situation, if you are separated with your kayak, you still have drinking water with you and both your hands are free for swimming.
The bladder holds 1.5 liters. In order to sip you need to grip the mouthpiece with teeth. There is no way out the drinking water to be contaminated, for example with seawater.
The hydration bladder can be used with vests of Palm: Extrem, Kaikoura, Peyto and Hydro. For other brands it is also possible, depending on the size of the PFD flap.