Abstract: A check assembly using compressible fluid for linearly dampening the closing movement of a door includes a cylindrical, hollow housing having a cavity defined therein with first and second ends. Slidably mounted within the cavity and attached to the door is a piston of substantially the same cross-sectional area as the cavity. The piston has flap-type, relief check valves allowing free passage of compressible fluid through the piston only during motion of the piston in the door opening mode. The check assembly further includes longitudinal grooves fabricated circumferentially around the cavity and of a dimension such that the seal of the piston against the cavity wall is broken at different points during movement of the piston allowing compressible fluid to flow from one side of the piston to the other. Finally, the check assembly includes a fluid bypass continuously communicating compressible fluid from one end of the cavity to the other thereby defining a closed loop system.