The Caldwell Hydrosled Shooting Rest holds up to 50 lbs of your choice of media. It is the most advanced recoil reducing shooting rest on the market and a rack and pinion elevation ram for precise adjustments. The advanced rear recoil absorbing pad protects firearm and shooter. It features 3.5 inches of horizontal gun fit adjustment to accommodate most rifles and shotguns. The elastic front retention strap reduces muzzle jump. It features easy portability when empty. The Fillable Reservoir will hold 16 lbs of dry weight, 35 lbs of water, 45 lbs of dry sand, and 60 lbs of pebbles.