Designed 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 water systems. The simple one way breather valve at the top of the vented loop allows air to enter the line when not in use, thereby preventing siphoning - and yet seals when water or waste passes through the loop. The duckbill one way valve is designed to seal even when particles are present in the fluid. Silicone duckbill valve - Long life with no perishing or hardening Constant internal diameter - No restriction to flow Self-contained mounting - 3 screw mounting posts give secure and easy installation Number Name Size Weight Color 90319 Vented Loops 19mm 37g 1.31oz WHITE 90321 Vented Loops 25mm 76g 2.68oz WHITE