This is what information i pulled up on the internet about these fiberglass tanks. These ones are outdated but can be filled at the reservations. There are 3 tanks selling at $35 Each cash deal.
Ragusa Cylinders are built with safety as the first priority. Lighter than aluminum and steel, this propane tank is made of a rugged, non-corrosive three-layer composite that was built with optimum safety in mind. It features a one-piece seamless inner layer and a visible gas level. Ergonomic handles make it easy to carry and stack. Has a QCC thread-on valve for QCC and POL connections. 17lb. capacity (4.7 gal.), 18-1/8"H x 12-1/2"W. Empty Weight: 10.3lbs.