Cammenga Phosphorescent Wrist Compass J5821 1 8" diameter. Black machined aluminum housing. Provides accurate, hands free land navigation in the most demanding conditions. When light conditions become dark, the 10 graduations become luminous, making the compass face easy to read. Accuracy + 40 mils. Operates flawlessly in temperatures ranging from 50 F to 150 F. Induction damping for quick needle stabilization. Maintenance free illumination for over 10 years. Heavy duty black nylon wristband.