I went to petco yesterday because their balls were on sale for $29 and i wanted to look at them...The sales person was telling me to not even buy one from their because they dont use heaters they just keep it humid and they use aspen as a substrate! the manager told me it keeps away mites ...but the ball I looked at was being treated for them and had them on him! I told them why aspen is bad for them but they didnt care. it was appauling ive never seen such horrible care in my life! thats probably why they were 50 dollars off because they were in such bad condition and would probably die.