FIA approved impact structures

Hello everybody,
I am building now a F1000 vehicle. I would like to get a homologation for the chassis spaceframe. Regarding the frontal and rear impact structures (crash box). From where can i buy frontal and rear impact structures? I want the impact structures to have an approval certification.

Any of the F3 chassis manufacturers should be able to sell you what you need.

Thank you for your reply! Very helpful.