Not all crash pads come complete with a strapping system like the Mad Rock Due to carry more pads with, and so the climbing community has invented multiple creative methods for getting numerous pads to the boulders without the need for multiple trips to the car. You can often use the handles on the side of the pad to tie them together with carabiners. You can also stuff smaller pads inside larger pads. If it has backpack straps, you also have two spare hands for carrying gear and more crash pads. You can also tie them together with compression straps... The possibilities are endless!