This is a BaBo insert to hold Anti-Vibration Feet.
The feet generally come in sets of 8, so if you have only one Bambu X or P series printer, you will have some spares.
This insert is 60x150mm or 2x5 grid units.
As a bonus, there is also enough room in the slots to store your original feet. Since these have adhesive on one side, I would suggest using a material like waxed paper to prevent them from adhering to anything else.
Printing:
See @Willi's BaBo System here: BaBo System
The author marked this model as their own original creation.