I have a melamean lid with a screen 3" in from the outside edge. It sits inside the tank for a very flush closure. Right now my new baby can't get out as it's strapped down, and he cannot get within 5" of the top of the tank! bad thing is, if my snakes get out, they are gonners, my cats will eat them in 2 seconds! Good thing the cat's cannot get into the cage, but they pretend to eat the snake from the outside! I have my two corns in my bedroom, along with my 2 chameleons. My bedroom is the reptile room! lol!