Caldwell Lead Sled Weight Reservoir - Adding weight to your Lead Sled Shooting rest couldn't get any easier than with the Lead Sled Weight Reservoirs. These reservoirs feature a leakproof bladder inside a durable 600D nylon outer case. A wide mouth opening for easy filling with materials like water, sand, or gravel. The collapsible design folds out of the way when not in use. Compatible with the Lead Sled Solo and Solo 2 models. The Solo Reservoir holds 1.6 gallons, approx. 14 lbs. of water or 22 lbs. of sand.