Mitutoyo Surface Plate Type Jaw for 552-Series Interchangeable Jaw Caliper Mitutoyo's 552-Series Interchangeable Jaw, Coolant Proof Carbon-Fiber Caliper allows you to maximize the investment of the caliper by changing the jaws on this caliper to best fit your application. By doing so, this 1 caliper can now do the job of multiple gages. Surface Plate Type Jaw Dimension a: 3.5" / 90mm Dimension b: 1.1" / 28mm Single Jaw Only Works with the following Mitutoyo Interchangeable Jaw Calipers... 552-191-10 (18") 552-192-10 (24") 552-193-10 (40") 552-194-10 (60") 552-195-10 (80")