I bought clips for my new (as of yet unoccupied) ball python tank. Those things suck! I couldn't get them to bend properly to fit my aquarium and screen top combo which were bought about 10 years apart. So I've installed $2 worth of velcro, and I struggle to pull the top off. I'm no Arnold Shwartzenegger, but I'm a little stronger than a hatchling BP, or so I hope! My amel corn also has velcro on a Sterelite and she's the corn I have who hasn't escaped! I definitely recommend velcro for smaller snakes.