Aluminum alloy, sheet, 1100 h12 (1/4 hard) specification astm-b-209; 0.385 in. O/a outside dia; 0.281 in. Inside dia; 1.573 in. O/a long; 0.011 in. Thickness of bottom of cup; 0.009 in. Thickness of walls of cup; 0.299 in. Outside diameter of closed end; used on body, apers mine, pract m33 and mine, apers, m18a1