Specification Brand : M & J Tooling LLC ItemName : New M20 X .5 6g Solid Thread Ring GAGES 20 0.5 GO NO GO P.D.'S = 19.655 & 19.593 - DW33371MJ ItemTypeKeyword : thread-gauges Manufacturer : M & J Tooling LLC NumberOfItems : 1 PartNumber : DW33371MJ ProductDescription : YOU ARE PURCHASING THE PICTURED RIGHT HANDSOLID THREAD RINGGAGES.