I needed to take my roborovski hamster to the vets to get her claws trimmed as they were starting to curl, but i hadnt yet bought a travel cage, so i thought i would try to make my own!
i was worried about a small storage box but i found this really sturdy and good quality one from B&M (english shop) it didnt have any holes for air so i drilled some holes in the lid, trying to spread them out evenly.
i really liked the fact the lid doesnt just sit on and it has 2 clamps on the side to keep the lid on, which i felt was needed to stop the hamster getting out
hope this was helpful