The H4 is the largest pack which USWE make. This is the one - it will easily carry required tools plus 2.5 litres of fluid whilst staying still across bouncy terrain. It will fit a trail tool, pliers, keys, phone, wallet, chain tool, small socket set, anything you need to stay maintained
We like them due to the robust and quality construction, the space but most of all the fact that when set up and adjusted correctly they just don't move or bounce like other packs so no tugging at shoulder straps or repositioning whilst you ride.
Loads of options for tools & personal belongings
Easy (and cheap!) to replace hydration bladder
Easy to unscrew adaptor cap plus silicone drink tube and 90 degree bite valve