Puckerings has dated this piece to the 1910s.

It is complete with brown leather case with hinged top and buckle fastener, wear commensurate with age / a section with perished stitching, also marked with the war office stamp and signed C. Deakin.
A great clean example in excellent condition. 3 1/2" x 2 1/4" x 7/8" thick. The case measuring 4" x 3" x 2".
Item: 43072
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Puckerings has dated this piece to the 1910s.
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