Raspberry pi 1 B model (old model, not B+) PCB doesn't have any mount holes. This plate allows rpi to be mounted on it and get mount holes.
It can be used with SD card (full size) or with low profile / half size SD-> microSD card adapter.
DesignSpark Mechanical v2 source file (rsdoc) included, so you can modify it to fit your needs.
Printed from PLA. Supports (optionally) needed for small holding slots.