Needed to mount a full size HID RP40 to an aluminum storefront door frame. Should work with most other full size prox card readers or many other devices that intended to mount to a single-gang electrical j-box and are 120mm x 80mm or larger.

Of course I know that narrow mullion mount readers are available but this allows a full size reader to overhang the adjacent window/sidelight so long as the frame has about an inch to the glass. Integrated j-box for the cable splice so you don't have to drill a large hole in the door/window frame to stuff the cable back into. Looks much better than screwing a waterproof bell box to the frame. "Knock-outs" (actually drill-outs) around the perimeter in case it's necessary to pipe in with 1/2" conduit though some lock rings might be a tight fit.

Recommend printing in PETG or other durable plastic especially if outside.

Fusion 360 .f3d and STEP .stp files included