Posi-Flate Inflatable Seat Valves are available in standard-duty and heavy-duty models. The 4 standard-duty categories: Series 485 Valves (1 piece housing [1 Pc Hsg]) in sizes 5" to 30"; Series 486 Valves (2 Pc Hsg) in sizes 2" to 30" (also available w/ SS 2 Pc Housing); Series 487 Valves (2 Pc Hsg) in size 4"; Series 488 Valves (2 Pc Hsg) in sizes 2" & 3". For the most severe conditions, POSI-FLATE offers 2 heavy-duty categories: Series 585 Valves (1 Pc Hsg) in sizes 4" to 24"; Series 586 Valves (2 Pc Hsg) in sizes 2" to 24".