This knob is the standard British made black Bakelite with white W for wiper switch with Lucas pattern hexagonal mounting as fitted Lucas Switches.

Fits on to the standard Lucas 1/4" hexagonal shaft with spring loaded retaining plunger.

Knob diameter  3/4" (19mm), Knob depth 1 & 1/8" (27mm). Note this is a high quality reproduction part.

Note; inset picture shows side and rear view with 1/4" hexagonal mounting hole. 

Also suitable for a wide range of Classic cars like; Morris, Mini, Austin, Jaguar, Hillman, Triumph, Allard, Armstrong Siddeley, Bristol, Daimler Jensen, MGA, MG Midget, Morris Oxford & Cowley, Rover, Singer, Triumph, Standard, Sprite, Vauxhall, Wolseley etc.