Found on everything from scope rings and bases, to autos and appliances. T-10 bit fits Brownells Scope Ring Screws.
1911, Issue:11, Page:053
1911, Issue:11, Page:055
Big Book Catalog, Issue:73, Page:147
Big Book Catalog, Issue:73, Page:149
Big Book Catalog, Issue:73, Page:445
Big Book Catalog, Issue:73, Page:447
Big Book Catalog, Issue:73, Page:475
Big Book Catalog, Issue:73, Page:486
SPECS: 1" (2.5cm) long. ¼" (6.3mm) shank. Set includes ten bits.