The Egerton- Chubb 10-12-16-20 Multigauge is supplied cased with setting masters to ensure accurate reading from a dial gauge.The gauge is capable of measuring actual bore diameter to .001 inch or less. The gauge has an entry depth of upto 16 inches . The stem of the gauge is grooved to show the correct depth for checking proof diameter. This gauge is or was, the gauge of choice used by the British gun trade.Egerton-Chubb,is/ was located in London U.K.

Roy Hebbes