Reduce crankcase pressure for optimum piston ring seal, fewer oil leaks and better engine performance. System includes two of each: chrome plated push-in breathers, check valves, weld-in 3-1/2" long threaded pipe adapters, rubber breather grommets and four hose clamps. Evacuation hoses not included. Use with 5/8" diameter hose. Reduce crankcase pressure for optimum piston ring seal, fewer oil leaks and better engine performance System includes two of each chrome plated pushin breathers, check valves, weldin 3.5 long threaded pipe adapters, rubber breather grommets and four hose clamps Evacuation hoses not included Package Weight 1.65 pounds