Tru Design Vented Loop 38mm Black - 90322Designed and made in New Zealand, TruDesign Vented Loops are the superior composite siphon break solution for marine applications. Vented Loops prevent water siphoning back into a vessel and thereby guard against accidental flooding and sinking. Vented loops are used predominantly in toilet to overboard applications, toilet inlet applications and holding tank to overboard applications. They can also be used in genset or small engine inlet cooling