Adjustable limit snap gages are an economical choice for the go/no go measurement of outside diameters or thicknesses. They are also known as AGD snap gages. Frames are machines from stabilized cast iron and are manufactured to ANSI B47-1-1988. Type C has a rectangular plate anvil and two opposing square headed anvils - all in hardened tool steel. These gages have the largest gauging surfaces and therefore longest life. Maximum parallelism error over adjustment range is 0.005mm (frame size 1-6X) or 0.008mm (frame 7-13X). Type U has knife edge anvils and is based upon the C Type frame - steel only. These are typically used for measuring external grooves. Standard anvil width and depth are 0.094" x 0.185" (2.4 x 4.7mm). Miniature range anvils are 0.03" wide x 0.079" deep (0.8 wide x 2mm).