This is the Carter Underwater Lift Bag Enclosed Pillow Lift Bags Features: Great for Shallow Water Recovery Brass Quick Disconnect for Fill Line One or More Handles and Tie-Off Points Easy to Handle In-and-Out of Water Fold and Roll to Compact Size Negatively Buoyant when Empty One or More Over-Pressure Relief Valves Durable and Strong Construction Urethane Coated Nylon Material Model Number Lift (lbs) Shipping Weight (lbs) Width x Height (in) Volume at Surface (63lbs/cu ft) CBEP-250 250 5 45 x 32 4.0 CBEP-500 500 9 56 x 36 8.0 CBEP-1000 1000 13 50 x 52 16.0 CBEP-2000 2000 22 86 x 52 32.0 CBEP-4000 4000 37 96 x 75 64.0 CBEP-6000 6000 46 96 x 87 95.0 Enclosed Pillow Bags are totally enclosed, with over-pressure valves to vent expanding air as they ascend. The advantage of Pillow Bags over Open Bottom Bags is that they can attain their maximum lift in much less water. For this reason, they are excellent for raising sunken boats and towing jobs. Like the Boulder Bags and the Ocean Salvage Tubes, all Pillow Bags come with brass quick-disconnect fittings attached to a short filler hose (connects to 1/4" pipe thread).