(Note: Measurements are outside max. dimensions unless stated otherwise).20th Century : Door knocker striking button plate.Diam. 37mm. (1 7/16")Supplied with 102mm. (4") x 6mm threaded rod. (Will need to be cut to length).Option : Square nut with chamfered sides.12mm. (7/16") x 12mm. (7/16") x 5mm. (3/16") (variable).Option : Octagonal capstan brass nut.Diam. 31mm. (1 3/16")Width side to side 29mm. (1 1/8")Height 18mm. (11/16")Option : Round bell brass nut.Diam 21mm. (13/16")Height 8mm. (5/16")