High Quality Professional Grade Tool This is the best companion for your BRIDGEPORT. Mounts with single pressure screw directly on machine quill, bypassing the working tool. Standard 1-7/8" clamping diameter. Test Indicator Features: Easy to read 1-3/16" white face with crisp black markings 7 JEWELS bearings Durable satin chrome finish Carbide probeGraduations: 0.0005'' per line Universal Holder Features: ALL METAL construction (washers are nylon) Clamping Diameter 1-7/8" Length from clamping bracket to indicator 4-1/2" Reach from 0-12" diameter Suitable for all indicators with 5/32" shank (stud) Adapts immediately for positive and fast indicating Mounts with single pressure screw directly on machine quill, bypassing the working tool Frame is designed with bearing pads properly spaced and an opposite pressure screw securing the rigidity of the mounting The desired stiffness is adjustable and is not altered by the pivoting of the jointsPadded case included!.