CPAP masks and hose/tube connectors are standardized – i.e., they are universally interchangeable. However, we are aware of an incompatibility issue with a few older CPAP masks. This issue inquestion is that the hose/tube connector gets stuck in the CPAP hose/tube when one tries to remove the older CPAP mask model. In this case, the hose/tube connector must be loosened and removed in order to resolve the issue.