This set of chamber gauges is an exact reproduction of a set used during the pre-war era by the proof house in Birmingham, England. The complete set contains one of each of the following sizes: .410ga., 28ga., 20ga., 16ga., 12ga., and 10ga. and will accurately measure all the standard chamber lengths that were available in each bore size. Each gauge is precision ground from the finest steel with the knobs fashioned from solid buffalo horn (knobs on the originals were bakelite). If you have ever purchased a gun only to find out later that the chambers had been altered you will appreciate the value of this set of tools and realize that they will pay for themselves many times over if you avoid only one such incident! The inexpensive flat-style chamber gauges will work in most instances, however, they can be fooled not worth the risk! The entire set comes in a beautiful buffalo hide pouch and will be a purchase you will cherish and use for a lifetime.