The Quickcenterer will allow you measure very accurately and quickly the center of any round object less than 3", like Anchor bolts EVEN IF THEY ARE BENT, rebar, pipe, and wall surfaces less than 10" high, plus outside 90%, 45% corners. No more grid layouts just plumb and shoot, let your computer do the rest. The QUICKCENTERER works by placing the device against the bolt or round object, surface or corner, level the prism bubble, shoot, and you can very quickly and accurately get the center measurement of the bolt, flat surfaces or corners. This is accomplished by attaching the adjustable head directly to a mini prism with bubble via the 5/8 X 11 threaded stud or to the bottom of a prism pole or mini pole via a connector nut, less height the better. Then by locking the bottom slide bar against top plate of the adjustable head to the correct diameter mark and by adding the correct shoe to the bottom of the channel bar, you than place the shoe against the object to measured. By using the attached shoe's front surface you can measure most wall surfaces and get 90% outside corners. A different shoe is used for the 45% outside corners. By placing the prism pole in between the Pole Height Extender Kit and attaching the adjusting head and shoe, you NOW can measure bolts or surfaces that are between 1" and to the height of the pole you are using. This gives you extra height to get over machinery or foundation walls. You can ALSO turn the Head around, (will need to plug in a known constant) and measure any vertical wall surface. Comes with the following shoes with sizes: Shoe One, (3/8, 1/2", 5/8", 3/4", 7/8", 1", 1 1/4", 1 1/2", 1 3/4", 2", 90%), Shoe two, (2 1/4", 2 1/2", 2 3/4", 3", 90%), Shoe three, outside 45%, one 5/8 x 11 threaded coupler, two pole extenders, plus 1 Allan wrench.Other shoes for different diameters or angles (even metric) can be special ordered.