iGaging Digital Caliper EzCal 6" and Brake Drum/Rotor Gauge Jaw Attachment Adapter Extension Digital Caliper 6" Brake Drum/Rotor Gauge Jaw Attachment Adapter Extension Range: 0-6" Accuracy: 0.001" Repeatability: 0.0005" Measures disc brakes drums and rotors. Contact points can be attached from the inside for rotors or outside for drums. Protective Case Included