Dozen 20 mm Diameter Small Inexpensive Air-damped Magnetic Plastic Compasses -- Great for Survival Kits Pack of One Dozen (12 pcs) Air-damped Plastic Compasses Great for survival kits, school science projects, hobbies, or inlaying into walking sticks or rifle stocks Ultra-low friction bearing with a highly magnetized compass needle Air Damped Compasses: No Liquid, No Leaking, No Air Bubbles Size (each): 20 mm (0.790 inches) in diameter, 7.25 mm (0.285 inches) thick, Weight (each): 1.4 grams (0.05 ounces)