mfr: ADJUSTABLE CLAMP All steel construction spring loaded outer guide accurately centers the drill. Steel guide sleeve retracts into its housing to ensure correct drilling depth. Self centering unscrews easily for cleaning; for use in wood, steel and plastic applications and is used with most electric and cordless drills. Size In=11/64 This item cannot be shipped to APO/FPO addresses. THIS ITEM CANNOT BE RETURNED. Please accept our apologies