Aluminum alloy; surface roughness63 microinches; o/a dim. 1.5 in. L by 1.164 in. H w/ irregularly cut corners; has 1 gear shaft hole 0.5001/0.5006 in. Dia; 3 gear shaft holes 0.1875/0.1878 in. Dia; 2 gear shaft holes 0.2500/0.2503 in. Dia; has 2 mtg holes