Forespar Marelon Vented Loops

An integral air vent in the nylon loop automatically prevents back siphoning into the toilet, yet seals tightly so there can be no leakage.
If your toilet is below the waterline, a vented loop should be installed in the discharge line. An integral air vent in the nylon loop automatically prevents back siphoning into the toilet, yet seals tightly so there can be no leakage.