Product Features：

1、Model: QLR--12 and QLR--16
2、Measurement Range: 12--16mm and 16--20mm
3、Accuracy： ±0.004mm
4、Proofreading ring：Φ16mm
5、L1：80 mm
A ： 0.5mm
6、Extension rod ：150mm

plese look the picture for more information

suitable to accurately measure the inside diamete of the blind hole and the through holes .
carbide measuring faces; Ratchet.
with a proofreading ring.
with a extension rod
paint plated on surface of the product