The Mitutoyo 368-164 Holtest Internal Micrometer has the following specifications:
Range: 12-16mm
Accuracy: +/- 2µm
Graduation: 0.005mm
Measuring Method: 3-Point
Contact Points: TiN Coated
Features
TiN-coated measuring contact points (over 6mm/0.275-inch range models) provide excellent durability
Impact resistance and allow the instrument to measure to the bottom of a blind hole (up to 100mm/4-inch models)
Highly durable because of carbide-tipped contact points (anvils up to 12mm/0.5-inch models)
Measure deep holes using an extension rod (optional) which is available on models over the 6mm (0.275-inch) measuring range
Setting rings for zero point adjustment is optional and supplied in the fitted plastic case up to 100mm/4-inch. Over 100mm/4-inch supplied in wooden case