I agree with AdoreRats. I travel a few times a year with them and have a small travel cage and a main cage for them to stay in while at destination. It depends how many rats you have. I have anywhere between 4-8 rats at any time. I used a smaller one for less but have found a small/medium dog/cat crate to work well for me. It holds their water bottle with a bowl under to catch water and hold their fresh wet food and another bowl for dry food. I hang a hammock up inside to sleep in and have a spitnick (they love sleeping in it) on the floor of it. They are secure and if there’s a sudden stop they either don’t react or just look around like why did you wake me up like that? The only thing that you’ll have to be careful of is the grate on the front door, it’s usually 1” squares but I haven’t had even a young rat try to get out, can always reinforce with 1/4”-1/2” hardware cloth/mesh. Also helps having a top door too. As always when getting anything for them keep in mind- chewing, sharp edges, escapable, easy to clean and ease of use. I always look in on them when I stop to make sure they’re doing ok. Also I listen to gentler music at a softer level, being mindful of their hearing.