Replacement Dry Box Seal and Inlet Seal for all PR System One REMstar humidifiers including both the older 50 Series models and newer 60 Series models.
The smaller Dry Box Seal connects directly to the water chamber and is designed to contain water in the humidifier water chamber and to prevent damage to the CPAP machine.
The bigger Inlet Seal is the gasket at the interface between the CPAP unit and the humidifier unit, and helps to ensure a water tight seal between the devices.
Don't let these wear out unless you want to wreck your CPAP machine and buy a brand new CPAP machine from CPAP-Supply.com! Hey, on second thought...