Round, brass, uniface, all stamped, 38mm. HJC/DERBY in a horizontal oval ring across the top, 69 stamped below. HJC represents the initials of Henry J Coles (a limited company from 1907). 

Founded in Southwark (London) in 1878 to manufacture cranes (many used in the railway industry), the company relocated to Derby in 1898 upon the opening of a large new site in Slack Lane. It manufactured a wide variety of cranes for UK and international buyers over several decades (internet searches, including Grace's Guide, give many examples).

“The Engineering Journal” 1909 carries a large illustrated advertisement for the company at its London Crane Works, Derby (ad not included in this listing). Although acquired by A.W.Farnsworth in 1926, the company’s name remained unchanged until it was again resold in 1939.

Please see my other ebay listings, I shall happily combine postage but this is not an automated process so please await my combined invoice.