The #6603-Series Walleye Prism System is ideal for Mining/Tunneling/Deformation projects.
 
It is compatible with all M20 screw-in type prisms and features a -40mm +,-2mm offset.
 
The flat bottom of the stainless-steel L-Bracket is a large 2.3 x 3.4 inches with five holes for mounting to a variety of surfaces.
 
It pivots in two axes and locks secure with a stainless steel screw and lock washer.