M.U.L.E. is short for "medium to ultra-long endeavours," and their new waist pack is the latest to be included in that category. It comes with a 1.5L bladder and a hose that's held in place magnetically, or you can ditch the bladder and carry a bottle on each side via pockets with straps that keep them from coming out.
You've also got 3.5L of cargo capacity (adding up to 5L, hence the name) from separate pockets on each side of the waist strap and a divided main compartment. If you've got too much stuff to fit it all inside, an adjustable bungee on top of the bag is a good place to carry a jacket or your kneepads, and there are also a few reflective touches added to keep you visible on the road.