Contoured, rugged design. Heavy-duty locking pin that attaches to clothing, keeps hands free. Sighting compass with large sighting mirror. Dial with 5 deg. graduations, inch & millimeter scales. Capsule contains: lifetime magnetized Swedish needle. Friction-free sapphire bearing. Permanently clear anti-static liquid & luminous points for use before sunrise or after sunset. 1/20" scale plus millimeter scale.