Prima Satin Chrome Octagonal Centre Door Knob SCP15A This item comes in 2 sizes SCP15A Knob 2 3/8 inch. (60mm) Back Plate 2 1/2 inch (64mm) SCP15B Knob 205/8 inch (66mm) Back Plate 3 1/8 inch (80mm) Solid Brass Architectural Ironmongery. These are hand polished and finished in Satin Chrome. A collection of door knockers, door knobs, letter plates and bell pushes. Also window fasteners, window stays, pull handles and lever handles. The Prima Satin Chrome Collection offers quality and elegance that cannot fail to enhance any property or style of decor. Sitting very comfortably with modern themes or art decor period