This Floppy Drive is fitted in my System 3, its in a 24HP wide, 160mm deep, 3U high module (Verotec 957-236390). It takes just two 100 x 160mm aluminium panels (i.e. Eurocard size) into each side of the module to attach the drives to. The panels are fitted in the right hand slots of both the guide rails, the 3.5" drives then just fit with a couple of 1.6mm thick spacer plates fitted to pack out the gap.
Internal View from Rear
Side View (right side)
Top View
Rear View