Mesh used
Aluminum window screen is used on most commercial screen cages, is available @ home improvement stores, and doesn't rust. The downside is some Chams will climb on the screen, and if done alot, the claws can be worn down. Do not use fiberglass screen, it can poke into the skin of Cham and keeper alike.
There is a Pet Screen that is softer at Home Depot that would solve this, but it is more expensive, and harder to see through, and only comes stocked in one size roll.
There are other meshes, but these are all I have worked with due to the fact loose bugs in the house are not a (comfortable) option for my marriage! Many of the Florida and California keepers can give you meshes they use in their outdoor enclosures that have holes big enough for feeders to pass through. That is, if you can have feeders visiting other areas of your home!