These are new old stock .2185 / 7/32" diameter, with a 1/4" wide screwdriver slot tip, for Yankee style (smaller) screwdrivers, like a No. 135 model Yankee, may fit other brand names as well. The screwdriver tip is 2.25" long overall, and has a chrome plated finish. There is no markings on these as to who made them, but the package is marked "CENTURY DRILL & TOOL CO CHICAGO ILL MADE IN U.S.A.".