Sometimes papers need to fit into a ring binder that can't be hole punched. Whether they must remain intact or a hole punch isn't available, the solution is easy with sheet protectors on hand. A sheet protector is a clear plastic sheet that is already punched to fit a three-ring binder. Use them for company training, archiving or portfolios. When shopping for sheet protectors, look for the thickness of sheets and durability of the area around the ring.