Carmex Threadmill Twin Insert Toolholder 30mm Cut. SR0030J21 2 5 16 Insert Height Format: The height 6 Knurls Revolving knurling tool 3 8" x 7 8" x 5 1 2" Multi Texture Diamond Insert Height Format: The height of the insert is designated in a diameter multiplier format (e Code: 4838 1 Code: 4838 2 Measurement Range Graduation Accuracy Range Graduation Accuracy Crown height 0 10mm 1mm ±0 It accommodates two inserts and utilizes S21 screws with a K21 Torx key for secure insert retention The SR0030J21 2 Mill Thread Toolholder is a high performance twin insert holder designed for efficient threading operations on CNC milling machines