One counter reads in the plus direction and another in the minus directiion, so incremental measurement can be made in either direction
Carbide tipped scriber
Made of stainless steel (except the base).
With driving wheel. With dial test indicator holder.
Supplied with dust cover
Optional accessory: clamp for protracotors (code 2372-CLAMP)

Insize 6881-A3, GAGE BLOCK ACCESSORY, holder, 2-4", 6928640316012
3M 22396, Roloc Disc 361F, 36 YF-weight, TR, 1-1/2 in, Die R150S, 7000045091
3M 26120, PPS Series 2.0 Adapter, Type S28, 17.5 mm Female, 19 TPI
Thread, 7100135956 