This tribrach has a circular leveling sensitivity of 8-min. 2.5 x magnification. Optical plummet focusing range is 1.5ft (.5m) to 50 ft (15.m). Universal 5/8 x 11 centering base plate, Tribrach is compatible with most precision tribrach adapters. Features: Leveling sensitivity of 8-min 2.5 x magnification Focusing range 1.5ft (.5m) – 50ft (15.m) Universal 5/8 x 11 centering base plate Compatible with most Tribrach adapters