[pet1971]

Hi! Everyone! ... Not sure if correct etiquette to ask a question here but have been trying to figure out something for ages and have giver up so I though I would ask the guy that would know lol!!... What are those things on the lower platform walls that look similar to a sliding volume control? they are about 6" x 9" with a black sliding button on it?... cant figure out what they could be used for lol!... thanks

Pete