This is a light-trap for tents and other use cases.

I build it for a 80mm fan, but used it for a 70mm intake fan from Aliexpress.

i also used a isolation to match the 10mm differnce

USB-Fan:

https://de.aliexpress.com/item/1005006195428823.html?spm=a2g0o.productlist.main.1.4e6dhj3Shj3Sjo&algo_pvid=96dc53f5-bbfe-4c70-a9bf-b325059ec364&algo_exp_id=96dc53f5-bbfe-4c70-a9bf-b325059ec364-0&pdp_npi=4%40dis%21EUR%2135.24%2110.22%21%21%21272.13%2178.92%21%402103888a17177587217038646e747c%2112000036219168571%21sea%21DE%211863011483%21&curPageLogUid=0ZGslc3xcYWD&utparam-url=scene%3Asearch%7Cquery_from%3A