Checked orifices are a series arrangement of a precision orifice, a ball check valve and an optional screen. The all metal assemblies are made of brass or stainless steel. Gas or liquid can flow in one direction only, at a rate established by the metering orifice. Reverse pressure differential does not result in reverse flow. Standard sizes are 10-32, 1/8" NPT and 1/4" NPT. Custom requirements will be reviewed for large quantity applications.