Simmons Improved Rocker Brass Gold sovereign scales
Manufactured in the mid 1800's to early 1900's
In fully working order and in good condition for the age of the item
10cm in length 

You will receive the exact pictured scale in its box

Please note wear and tear to one end of the box as pictured
A very clever design and a scale still current and usable today.
This is a balance scale for full and half sovereigns which also measures the circumference and the thickness.
As gold is one of the heaviest metals one way to forge a sovereign in brass would be to make it slightly larger to make up the weight.
This clever invention puts a stop to that.

1