clamp for kis C Box cube 27L
box can be bought in OBI stores

for perfect airtightness use 16 clamps and sealing tape between box and lid

print with any material, any layer height, 5 perimeters

https://www.kis.it/en/singola-variante?id=39615

If you are having problems installing the clamps, you can start from corners and push them to their position.

I put them in between ribs on longer edges and next to handles on shorter edges. At corners, I aligned them with corner rib endings.
Clamps also work as centering tool when stacking boxes.