Spindle-Mounted Indicator Holder Arm, Arm Type Articulating, Compatible Indicator Mounts 3/8 in, Maximum Reach 7.244 in, Working Length of Post/Lower Arm 4.016 in, Working Length of Upper Arm 3.228 in, Construction Steel, Includes Snug Yes, Screw Type Metal Knob, Centering Arm Shank Size 3/8 in (Dia), Centering Arm Shank Type Straight