The US-10 retro fits to Hydro 3 to increase capacity by 10 litres.

Reversible:

1. YKK water resistant zip pocket.
   
   
2. Coated-mesh pocket.

Fitting Instructions :

Use the 2x ladderlock buckles on the sides of the Hydro pack, as the larger 10 litre pack benefits from added compression. It is not necessary to use the male buckles when the coated mesh pocket is on the front.