The Lightning Phantom Idler Kit includes a Power Idler, a Return Idler, two Singe-Sided Clamp-On Chain Keepers and the necessary hardware to make it work. This kit provides smooth, quiet, long lasting performance.
Note: Some of the older Lightning bikes require a smaller diameter idler. If you have an older bike, please check to see if you can fit a 2.75in (15 tooth) idler in back. To check, measure the clearance from your old idler to the seat frame, then measure across your old idler. If the combination measures less than 2.65in, you will need the smaller idler (14 tooth).
The return idler doesn’t work because it’s too large and interferes with the drive chain. The power idler works as designed.