This is simple humidity meter holder bor dry boxes. It is made for https://www.aliexpress.com/item/33037396704.html?spm=a2g0o.order_list.order_list_main.343.7efa1802VAgLtJ
this meter.
Humidity meter just clips into holder and for fixing holder to box use M3 bolt and nut.
The author marked this model as their own original creation.