Standard size: 3/4 inch thread fit most standard American hose. Drain hole is able to drain the remained water in the pipe.Please keep away from the product when turning off the water, remained water will be sprayed out. Temperatures: Max. operating temp. rating: 180°F/82°C, Max. operating pressure rating: 125 PSI. Application:Breakaway set screw for permanent attachment. Headless Hex Set screw for removable installation. Eliminates back-siphonage into water supply,anti-backflow valve for RV, garden spigot, outdoor water faucets, hose bibs, hydrants. HIGH QUALITY: Durable brass material stays longer; Meets ASSE 1011/CSA B64.2, Meets ANSI/NSF 61-9 PACKAGE INCLUDES: 3 × Vacuum Breakers,6 × Washers, 6 x Headless Hex Set screws,1 x Allen Wrench, 1 × Thread SealTape . ATTENTION:not for fine thread. Standard size:3/4 inch thread fit most standard American hose. Drain hole is able to drain the remained water in the pipe.Please keep away from the product when turning off the water, remained water will be sprayed out.