The Tru-Flate 13-201 Coupler/Plug Set includes a 1/4" Female NPT Coupler and a 1/4" Male NPT Plug. This set is designed for use with air compressors and air tools. The female coupler features a 1/4" NPT thread that allows you to connect it to the air hose, while the male plug is used to connect to the air tool.