Leica Style optical tribrach feature specially designed optical system allows for quick and accurate checking & adjustment of the optical line of sight. It is recommended for accurate plumbing of Total Stations, GPS Systems, reflector systems & other accessories. This tribrach features a twist-focus (2.5X mag.) and leveling screws with center line. It has an 8-min vial, 3-prong forced centering and a 5/8 x 11 base. Will work with most survey instruments and accessories manufactures such as: Topcon, Sokkia, Trimble, Nikon, Leica, Pentax, Seco, CST, Omni, Etc.