A brass and steel mechanical standard yard comparator, in a mahogany case, by W. T. Avery of Birmingham.
The brass standard yard is by De Grave, Short & Co of London, marked with Royal ciphers and portcullis marks. The yard is subdivided into Feet and inches, the first three inches are further subdivided in to 1/100th, 1/12th and 1/16th of an inch.
Made for the County of Devon. Indenture number 4701.
Brass name plate to case lid marked: STANDARD COMPARATOR COUNTY OF DEVON W & T AVERY Ltd, LONDON
Marked with royal ciphers for George V, George VI, and Elizabeth II, and portcullis date marks, 1936, 1947, and 1956.