Griffin Universal Brass Ground Joint Reamer
This brass reamer is 7mm at it's smallest point and expands at a 1-10 ratio taper. It has been machined to +/- 0.001". This means when you ream a fitting it should be a nice snug joint connection with little effort. This universal reamer size range is just taller than a 10mm fitting on the small end and just wider than a 19mm fitting at the widest point.