If you are looking for a tool to calibrate your measuring equipment or to gage parts directly, the VERMONT GAGE 301110040 Go/No Go Plug Gage Assy is what you need. The chrome plated 70/72 Rc finish provides corrosion resistance and enhances the look of this go/no-go plug gauge. This taperlock plug gage measures 5/16″ in length for the go part and 7/32″ in length for the no-go part. It has a #4-40 UNC thread size with an overall length of 1 3/4″. You will be able to work with precision when using this VERMONT GAGE Go NoGo Plug Gauge Assembly.