Proximity reader spacer

We had a new access control system installed, and were getting weird "double reads" from one of our doors. Turns out that the two readers on that door were too close and it was possible for them both to read cards simultaneously, so I printed these 15mm spacers to provide enough "gap" to stop the double reading.

They are sized for this particular sort of reader, but you could use them as the basis for a more general reader spacer easily enough.