Its a MOSFET holder for standard ANETs acrylic frame. MOSFET is located above the control board, where it could be passively cooled. Holder fits into prepared holes in acrylic frame, no extra drilling required.
There are two versions, the second one (red) is shifted more backwards, so insertion of SD card into slot on ANETs control board is more comfortable (but it is possible also with first version (blue)).
Printed from PLA, resolution 0,2mm.