You should definitely try to get aluminum mesh. Other meshes are often made of fiberglass. Crickets can chew right through it. Not only can they escape, but if they don't escape before the cham eats them, the cham then eats fiberglass. True, it's a very small amount, but it could still be dangerous.
Yeah, I'm not trying to scare you, I just remember studying the same thing early on. I like to play it safe. I think door screen is usually fiberglass but I'm no expert
At least mesh isn't terribly expensive.
I second others opinions; "window screen" is standard fiberglass and crickets will chew through it. Aluminum is the general way to go, although I have heard of some using a coated "petsafe" mesh (but that is more expensive, i dont know much else about it never seen it)