This fitting bypasses the leaky arrowhead PK1390. It does not provide back flow protection if it is required in your area. It is for Non Potable water. Sometimes when removing the old vacuum breaker it will come apart in the middle you must remove all of the vacuum breaker from your faucet to install this bypass. Attention California Residents: WARNING: This product contains chemicals known to the State of California to cause cancer, and birth defects or other reproductive harm.