"HUB MATL-ALUM. ALLOY 6061-T6;BRAKE LINING MATL-POLYURETHANE;FINISH,CHEMICAL FILM PER MIL-C-5541,CLASS 3;O/A 1.500 IN. LINING BONDED TO HUB,CNTR HOLE DIA 1/2 IN.,4 HOLES 0.096 IN. DIA THRU C/BORED 0.156 IN. DIA X 0.040 IN. DEEP;4 RIVETS SOLID COUNTERSUNK 100 DEGS"