These pre-joined drive bands will fit perfectly on your Echo, and options are available for all the different bands based on attachments or accessories!Standard: Fits Echos without the Accelerator, or a "Standard" wheel!Extended: Runs from the Drive Wheel to the 4A Accelerator.Accelerator Band: Runs from the 4A Accelerator to the Flyer. Treadle Hub Band: This connects both treadles together to hide the bearing beneath them. It hangs on two screws/pins that it pulls together. If you don't see this near the hub, you don't have one! Newer Echos don't use this band & have a different method of hiding the bearing.