Product Description The combination square with center head is a basic combination set. The center head is a convenient and accurate way to find the center of round work. Starrett combination square consist of a machine-divided, hardened and tempered steel rule (or blade) on which is mounted an adjustable square head. A reversible lock bolt allows the blade to be turned over or end-for-end without removing the lock bolt or nut. This ensures true alignment of the blade and heads. Square head are made of cast iron and are not to be confused with the cheap imitation plastic or die cast heads on the market. The value of Starrett tools is that they are accurate and will last. As the name indicates, this tool can be used for many different purposes - a complete substitute for a whole set of common solid try squares, a 45 degree miter, a depth gauge, a height gauge, a marking or scribing gauge, a level, a plumb and, by withdrawing the blade, it can also be used as a precision rule. This saves littering the workbench with too many tools, each being necessary but may be used less. This results in the goal of all good craftsmen - better accuracy and greater efficiency. From the Manufacturer Starrett combination squares are perfect for all craftsmen, offering better accuracy and greater efficiency. With reversible lock bolt, scriber, spirit level Graduation: No. 4R - 1/8", 1/16", quick reading, 1/32", 1/64" The square heads are forged hardened steel with smooth black enamel finish Square blade easy-to-read, sharp graduation Square head and center head bearing surface are accurately ground 4R Grad: 8ths, 16ths, Quick Reading 32nds, 64ths Smooth Black Enamel Finish Center Head Satin Chrome Blade Specifications for this item Brand Name Starrett Item Weight 1.00 pounds Measurement System English Model Number C33HC-12-4R Number of Items 1 Part Number C33HC-12-4 Product details User Guide [406kb PDF] Product Dimensions: 1 x 1.4 x 12.3 inches ; 1 pounds Shipping Weight: 1.4 pounds