HHIP internal dial caliper gage features 0-1 inch movement to check recessed diameters, internal bores, etc. Set with micrometers or a ring gage. Bezel can be rotated for zero setting and can be locked with screw. Carbide ball measuring points: 0.09 inch x 0.09 inch button: push to close arms. Arm Length: 3.25 inch arm thickness: 0.09 inch product specifications: range: 0.375 inch -1.375"; graduation: 0.001"; a: 5/32"; b: 5/32".