Adaptor with  Optical Plummet Adapter accepts all mount and target assemblies; has 60" level vial for accurate leveling and centering that’s adjustable to match height of optical axis above the tribrach. High-quality tribrach features 3X magnification and a twist focus. Its reticule is composed of two small concentric circles. A locking forced-centering knob, a 5/8 x 11 base and an 8-minute circular vial.