They are just the standard size, same as a credit card. They don't have any holes in them. We included key card holders in our OOT bags and they were a huge hit. I would definately recommend them for your OOT bags. We did have a few problems with the cards while we were there, they would often stop working so we would have to go to the lobby to get new ones. They said at the front desk that if you put them near any electronics, cell phone, camera ect that they will stop working.