The CRL Mini-Spot Glass Etcher Blaster is designed to spray abrasives for glass etching within the confines of the rubber boot. As the sprayer is used the abrasive is siphoned from the bag, shot against the glass, blasting an area approximately 1-1/4" (32 mm) diameter, and is then drawn back into the recovery bag for reuse. This Blaster is to be used only on vertical flat surfaces where the boot can make complete contact with the surface. Required air supply is 20 cfm (9439 cm/sec) @ 80 psi (5.5 bars).