Aluminum broze ams 4640, 3.808 in. Min to 3.818 in. Max o/a lg, 2.067 in. Min to 2.069 in. Max o/a w, 0.937 in. Min to 0.938 in. Max o/a h, machined surfaces 16.0 and 250.0 microinch finish, 1 mtg hole through tapped 0.250-28 nf-3b thd, 2 mtg holes through tapped 0.375-24 nf-3b thd