It’s a 3-liter Camelbak Hydration System [two of them] in black of course. The bladder is a bit smaller than my Fastback Bladder and will fit better into the Goblin Cricket Storage Pockets. I still plan to use the insulation bags. There is one major difference in the two systems.

The Fastback Systems uses a shut-off valve to stem water flow when the hose is disconnected. The Camelbak requires a plug [right] to cap the water. This adds special challenges should I desire to remove the bag for refills. We will just have to see how that goes.