Brunton - Ball and Socket Mount for Pocket Transit/Compass DURABLE - The lightweight aluminum and brass construction lends to years of field reliability. ACCURATE - Slide the compass into the mount, tighten the brass thumb screw, and hold the compass level for azimuth and inclination readings more accurate than those acquired by hand holding the compass. STANDARD - Standard -20 UNC thread. CUSTOM FIT - Fits Brunton Transit exclusively. MADE IN THE USA - Made in Bruntons own facility in Riverton, Wyoming.