Long, continuous lengths in coils as indicated below. Conforms to performance specifications for appropriate working pressures. Approved by National Sanitation Foundation for drinking water use. Made of black virgin polyethylene. Requires special copper tube size connectors. Limited by 25 year warranty. Pressure rating per square inch at 73.4 F. : 200 P.S.I. No. 18515: 3/4", 100" copper tube size No. 18520: 3/4", 500" copper tube size No. 18535: 1", 100" copper tube size No. 18540: 1", 300" copper tube size