The reinforced bead elbow fits on the bottom of the downspout. It is basically the “bottom elbow”. However, the product’s lip is gently curled back, making the end smooth and gentle to the touch. This is to try and minimize the risk for any cuts. The top is expanded to fit outside the large end of the downspout. This means you can cut the bottom part of the downspout off and use it as a bridge piece. If you do not need the full 10’ length of the downspout. The RBE of course fits on the preshrunk end of the downspout as well. To fix the RBE to the downspout, secure it with a couple of short (5/8”) self-tapping screws to the rear sides of the product. These are the only screws you ever use that penetrate the system.