Have you ever had a digital scale show that products are being pulled through an HFI injector even when there is no car in the wash? Your cost per car can easily double when injectors continue to siphon the chemical after the vehicle goes through the car wash. HFI now ships anti-siphon kits with their systems to prevent this, but during an install, these parts often get overlooked. Trust us, they are worth the time to install… you will see why if you notice product still pulling after the injector shuts off, or if the amount of chemicals being used seems to be more than it should. The anti-siphon kit reduces the effects of water hammer and prevents drawing concentrated chemical into your solution line when the valve is closed. The kit, HFI Part #1001436, includes 5 pieces and is for use with 1/2″ OD poly flow.