Starrett I.D micrometer 4-24 no. 823G
I purchased these as New Old stock they were brand new still had the wax on the ends I marked all of my ends with green paint marker so they could never get mixed up and they are extremely reliable I just checked with my four to five and my 5-6 OD Mics and they are right on I have all original paperwork and they were always kept with a piece of oil paper these are in extremely splendid condition all of the threads are in impeccable condition everything tightens up as should the lock on the dial works great like you would expect from starrett