I bought a four piece pack of PWM regulators (see link at the end) to use old pc fans as fans for my reptiles. Then I designed a case for these regulators including mounting options.

This is not an affiliate link, nor do I want to advertise exactly these regulators, but these are the one i designed the case for and it is an exact fit. You might get the same ones from other websites and dealers, so the link is just for reference.

A also desined honeycomb fan cover, so my reptiles can not touch the fans (see my profile) and attachment brackste for the fans for 120mm und 140mm fans.

You will also need:

• 2x m2x20mm flathead screw or similar
• 2x m2x10mm flathead screw or similar
• 4x m2 hex nut 

The shorter screws are to attach the board to the case and the longer ones to close the case.

The mounting points are designed for 3.5x16mm wood screws, so every similar screw with a conic head should fit, alternatively use some washers for flathead screws.

I used PLA, PETG might be fine, too. Can be printed without support.

[https://www.amazon.de/Drehzahlsteller-Drehzahlregler-Spannungsregler-Einstellbarer-Fahrerschalter/dp/B09KNKQ7GJ/ref=sr_1_7?crid=3MD9OEU2MAJCU&dib=eyJ2IjoiMSJ9.xr5oDk4HBJRW7aG7oyIZVQvbAO7K9azonz3MziwQUcKU38ruJaCSfv-ZyEfB1iPuaI6dIhf8oj0wY1gKn1ud3Fr97dSPMXzUMUoNe7jgSQnY9qD-itQdVIgExb2drETefVjt8RO0ykki07QmRSwctIxjXOF5NzU3fE4BJUTmlE3oVE86vRXq-B1vYorCB5xk36mx64wWFWA6UciF-O3YCpWPiRzjkoED7dnK96l7S2QkQgfieN9WnuiJtDhOwtLQ6Ms6J6_GI5SvggMpgiVfGykTIhBgyM0hrUPGF5UMzcM.JbqfSHhEeOVQu2Ex9OC1udH3GJm4hus6WNuG3C5zvjE&dib_tag=se&keywords=voltage+regulator+12v&qid=1720973577&sprefix=voltage+re%2Caps%2C98&sr=8-7](https://www.amazon.de/Drehzahlsteller-Drehzahlregler-Spannungsregler-Einstellbarer-Fahrerschalter/dp/B09KNKQ7GJ/ref=sr_1_7?crid=3MD9OEU2MAJCU&dib=eyJ2IjoiMSJ9.xr5oDk4HBJRW7aG7oyIZVQvbAO7K9azonz3MziwQUcKU38ruJaCSfv-ZyEfB1iPuaI6dIhf8oj0wY1gKn1ud3Fr97dSPMXzUMUoNe7jgSQnY9qD-itQdVIgExb2drETefVjt8RO0ykki07QmRSwctIxjXOF5NzU3fE4BJUTmlE3oVE86vRXq-B1vYorCB5xk36mx64wWFWA6UciF-O3YCpWPiRzjkoED7dnK96l7S2QkQgfieN9WnuiJtDhOwtLQ6Ms6J6_GI5SvggMpgiVfGykTIhBgyM0hrUPGF5UMzcM.JbqfSHhEeOVQu2Ex9OC1udH3GJm4hus6WNuG3C5zvjE&dib_tag=se&keywords=voltage+regulator+12v&qid=1720973577&sprefix=voltage+re%2Caps%2C98&sr=8-7)