Sterling silver cuff bangle with etched '50's inspired design.  It has a gentle anticlastic curvature and an oval profile.  It is available in 2 widths:- 25 mm and 20 mm. Full dimensions below:-
25mm wide with 30mm opening and internal dimensions of 65 mm x 55 mm
20 mm wide with 20 mm opening and internal dimensions of 70 mm x 60 mm.
Hallmarked. 
Other sizes can be commissioned.