TruArc? 7 mirrored compasses feature an inclinometer for measuring apparent tree heights and gauging avalanche danger and can be used as a sighting tool for even more accurate headings. TruArc? Global Needle system and tool-less declination compensation ensures worldwide compatibility. Dimensions: 2.9" x 3.9" x 0.8" (7.4 x 9.9 x 2cm). Wt: 2.2 ounces (62 grams). TruArcTM Global Needle; Ever-north Magnet; 2 degree resolution; Sighting mirror; Clinometer.