(Note: Measurements are outside max. dimensions unless stated otherwise).
19th Century : Solid Tudor rose backplate concave towards centre.
Diam. 57mm. (2 3/16")
Height 7.5mm. (5/16")
Hole 5mm. x 5mm. (3/16" x 3/16")
Thickness at centre rebate 2.5mm. (1/8")
Diam. of inside rim 11mm. (3/8")