Head Gasket
Coleman Sanborn Oil-Free Pumps Parts

Price: $7.03
Found under the following brands:
Annovi Reverberi-AR, Westward, Bostitch, Black & Decker, Craftsman, Devilbiss Air Power, DeWalt, Emglo, Excell, Porter Cable, Speedaire
You will need this gasket when replacing the valve plate or the head.