The second timepiece is this unique Tudor Heritage Black Bay One reference 7923/001. Inspired by the historic 1954 Tudor Submariner known as the reference 7923, the timepiece features a 41 mm steel case with polished and satin finish and a Domed sapphire crystal. Inside is the self-winding mechanical movement, Tudor calibre 2824 with a power reserve of approximately 38 hours. Completing the ensemble is a steel bracelet with tube-type attachments and folding clasp and safety catch; Two additional straps supplied with watch: one in darky brown aged leather and one in grey fabric. This unique timepiece will be sold during the Only Watch 2015 charity auction.