It could be little too big depending on the cham that will use it. I usually cut a 16oz colored(opaque) cup in half. Refrain from using transparent deli cups since, your chameleon will likely to be confused and shoot its tongue to the outside of the cup thinking that its shooting directly to the insect inside.
I saw this idea somewhere else and has made a BIG impact on my guys feeding. Basically it is a 1/2 gallon milk container cut down with screen glued to the inside.
They do crawl up and down the screen. They also stay there just about 100% of the time, even when he is eating. I do let a couple loose in the cage so that he can hunt, but I put most in there.