Tubing is one of the most common replaceable parts of the CPAP treatment due to wear and tear, which may cause leaks. Standard 6 foot length used as a connection between the CPAP device and the Mask Interface.
The interior of the tube as smooth allows air to flow without turbulence.
Corrugated exterior provides excellent flexibility as moving.
22mmID connectors conform to ISO-5356-1 standard; it fits most CPAP machine and interface used.