This is a new stainless steel Round fan gauge. 
 
Suitable for measuring the diameter of diamond, gem and agate beads.
With professional size scale on the surface, it is a very practical tool for jewelers and jewelers.
With the help of this sizing gauge ,you will get a fast way to calculate the size and weight of a diamond.
 
 The measurements are by Carat weight and it measures approximately 35mm closed.