High Density, Cross-linking Polyethylene withtargeted thickness of 1/4" for superior strength. No welds or seams to fail or leak. Will not crack even at 150º F above or 160º F below zero. No possibility of rust...EVER. Five year warranty on all tanks. Most tanks include a new O-ring/lock ring or gasket. 1973-1981 Chevy/GMC® Pickup with 8' box 20 gallon tank. Fits right or left side. Includes new lock ring and O-ring. 54" long.