GURU A diving companion you can trustGuru was studied, designed, and engineered for a mainly recreational user who is beginning to demand a bit more. More specifically, the SWS weight pocket system can hold up to 6 kg, while the roomy pockets with YKK zippers feature a knife slip and the backplate cover with anatomical inserts ensure the utmost comfort. Material outer bladder: PU coated 1000 D Cordura Material inner bladder: PU coated 1000 D Cordura Dump valves: 3 with pull command D-rings: 4 - 40 mm in stainless steel + 2 - 25 mm in stainless steel Dry weight (size L): 3700 g (complete with hose and weight pocket).