The ResMedCPAP Tubing is a universal tube that can be used with any CPAP or Bi-Level machine as well as any CPAP Mask. ResMed's tube differs by the material at the end, or where the mask and machine connect to the tube. The material is slightly more stiff than the other tubes on the market. The tubing exterior is corrugated which allows for maximum flexibility. 6ft in length is considered a standard length for a tube in use with a CPAP or Bi-Level. Tubing should be replaced every 6 months.