Gerson G11E Face Mask Respirator Pre Filter Pads x 10. Contains 10 Filter Pads to place into the cartridges . Fits Gerson  8000E and 9000E Series respirator which we also sell. The Gerson Respirator is a Half mask paint spray respirator featuring easy to replace twist-on cartridges and snap-on prefilter retainers. The durable, reusable facepeice is designed to be used over and over. A low maintenance respirator where only the cartridges or prefilters need to be replaced.