This is a simple humidity sensor mount for your filament drybox.

Should work fine with any transparent storage box. Round hygrometer can be purchased on e.g. Aliexpress or Amazon.

When installed (3.5mm drill needed) the hygrometer just slides in from the top and remains easy removable to replace batteries.

The origin design was perfect for my needs except for the fit of the screws / nuts. Therefore I remixed the front mount to fit easily heads of ‘normal’ hex socket head cap screws (SHCS) and modified the back part that M3x8 or 10mm screws will fit without nut. Just screw the bolts into the plastic but do not over-tighten. Material to be PLA or better.