Swanson Tool S0107 12-Inch Speed Square Layout Tool with Blue Book Product description All products are imported from the USA. All electronic products must be used with a step down/up converter for Indian voltage compatibility. 				    	 					 From the Manufacturer Swanson's Speed Square is a popular pocket sized square that incorporates features of the framing square, tri, mitre, and protractor squares. Common rafter and hip/valley rafter scales permit one-number references for all cuts. The square is merely rotated to the proper roof pitch value on either scale to assure the correct angle cut. The slot along the scales will accommodate an adjustable locking pin for repetitive cuts using any 1/4-inch bolt and nut. Comes with a handy, 62 page pocket sized booklet that provides vital instructions, reference diagrams, and tables for the construction of roofs and stairs.