Fowler High Precision Fowler's high precision Angle Blocks are made of solid, hardened steel with specific angles. Includes 1?4 and 1?2 degree sizes to handle most angle requirements. Blocks available in sets or individually. Each 12 block set includes 1 thru 5° blocks in 1° increments and 5° through 30° blocks in 5° increments as well as 1?4° & 1?2° blocks. Accuracy ±2.5 arc minutes Use of the Solid Angle Block simplifies the setting and checking of angles during tooling, production or inspection. This fast, accurate method eliminates time consuming calculations, sine bar and any setup errors. All blocks precision ground. All blocks are 3" long and 1?4" thick.