Wall bracket parts for BECO 254 & other similar wall / ceiling lights mid century vintage lighting

Wall bracket part only. Light not included, shows example of part being used. 

Lighting wall mount / bracket to fit BECO 254 wall lights and or other similar wall lights and ceiling lights. 

$23 each 

Sizes available- 
55 mm
75 mm
80 mm (fits BECO light show in picture)
90 mm