The rainfly does not fit over any size sleeping pad. Unfortunately instead of placing the attachment points for the sleeping pad on the bottom of the pack to avoid issues Osprey chose to put them closer to the center making it impossible to attach the pad and use the rainfly simultaneously. I had to walk down a mountain in the rain carrying my sleeping pad. This is not something any hiker wants to do, let alone six months pregnant. Makes for a very dangerous situation. I don't think I will be purchasing any osprey products in the future. For the price, more thought and testing should have gone into the design.