Vintage Smith's 30+ 30 - amps meter original came out of a mini we believe this is working although not tested would look fantastic in a classic car or just a great decorative piece (see pictures) got that aged look classic car enthusiasts want original as much as possible 5 1/2 cm round 5 1/2 cm depth 
Smiths was a UK-based company that manufactured gauges and other instruments for British cars, including speedometers, tachometers, and amp meters. The company was founded in 1851 by Samuel Smith as S. Smith and Son
History of Smiths gauges
In 1904, Smiths delivered the first speedometer to King Edward VII for his Royal Mercedes. 
In 1907, Smiths opened a new factory in Watford to meet demand for their products. 
In 1913, Smiths moved their motor accessories production to Speedometer House in Great Portland Street. 
In the 1930s, Smiths made amp meters for school laboratories and demonstration theaters. 
In the 1970s, Smiths sold their automotive business to Lucas, who then sold it to another company. VDO later acquired the business. 
Other Smiths products
Smiths also made watches, clocks, and jewelry. They were one of the largest watch producers in Europe before winding up their business in 1980.