This is a 120mm fan mount, that I designed while building my RatRig V-Core 3.1, such that it could be mounted on top of a BTT Octopus V1.1 board, while being mounted on a DIN rail.

Made for DIN rails with the following specifications:

DIN rail with holes (18 mm between each hole). The rail is 35 mm wide and 7.5 mm high. Any length.