Use this 12 inch stainless steel Center Finding Rule to quickly and accurately find the exact center of circles, squares and rectangles without tedious mathematical calculations. A valuable tool for woodworking, graphic design, model making and all kinds of D-I-Y projects. Easy to use...simply equalize the readings on each side of zero and mark the center at zero. Reverse side has conventional scale graduated in 64ths and 32nds. 1 inch wide x 12 inches long.