Our Spinders (sounds like Binders)are a standard 3 hole punch. They have a double locking mechanism and adhere to your ScrapRack base with a commercial grade of Velcro type fabric. Each Base unit will hold 7-8 Spinders. Each TravelPack Plus will hold 2-3 Spinders. Having a few additional Spinders can make travelling to crops and classes fast and easy. Sort and Load your photos by layout group into pocket pages, add journaling notes, memorabilia, and specially purchased items, hook them all together on an additional Spinder and you're ready to crop.