The weakest part of a mesh cage is where the tray slides in
These supports are designed to help this situation
I can fit one at each side of the chinchilla cage, or such cages with a slide out under mesh tray
Recomended with larger cages, due to excessive weight of extra shelving, heavy toys etc. used in the cage
Or ideal if stacking cages (one sat on top of another)
Not easy to fit yourself, so is better if I fit if required on cages purchased.