U Adapt-It Disposable Straight Connector allows the connection of an oxygen concentrator to a CPAP machine. One end attaches to the CPAP machine, while the other end affixes to CPAP tubing. The middle spigot attaches to oxygen tubing. Once the connection is made, this allows users to successfully receive oxygen therapy during use of CPAP. U Adapt-It item number 004084. 22mm outside diameter on one end and 22mm iinside diameter on the other end fits most CPAP tubing.