A special double-ended hex adapter for 2 sizes of pin-inhead security fasteners. The adapter inserts into both ends of the 216 C tool. Has a 5⁄32 in. (3.96 mm) hex and a 5⁄16 in. (7.93 mm) hex - both with center holes to fit over special fasteners with a pin in a recessed hex. The 5⁄16 in. (7.93 mm) hex has internal threads forrethreading binding posts.