Vented LoopVented loops are anti-siphon safety devices for use with both manual and electric marine toilets installed below the waterline (static or heeled), Product : JABSCO 1"" VENTED LOOP ANTI SIPHON SAFETY DEVICE F/ TOILET Manufacturer : JABSCO Manufacturer Part No : 29015-0020 UPC : 671880529501 SKU: CW31422