Hi, I strongly advise against using PD doors. I installed 2 PD doors last year and it broke twice. You need to get all your guests to watch a demo first before using these doors. And now that I inspect more closely, I suspect the part on one of the doors was already broken and the PD guy just glued it back when they first install it... now I think I know why that guy told me NOT to clean of those yellow stains which he claimed was oil to lubricate the tracks...