Oatey 3 in. PVC Air Admittance Valve 6-64-639-03 These are great for lining

These are great for lining up all your screwdrivers

NS-OMC for Ace no

and watch as the machine blasts out a stream of impressive bubbles

Opening Length: 2 in

Oatey 3 in. PVC Air Admittance Valve 6-64-639-03 These are great for liningThe purpose of an air admittance valve is to provide a method of allowing air to enter the plumbing drainage system without the use of a vent extended to open air and to prevent sewer gases from escaping into a building. An air admittance valve is a one way valve designed to allow air to enter the plumbing drainage system when negative pressures develop in the piping system. The device shall close by gravity and seal the vent terminal at zero