How do I remove SHOWER DOOR GUIDE?

Thanks for posting. I believe you need to remove the bottom rail before you can remove the 10-216. First, you will need to remove the door and lay it on a flat surface, like a table or a pair of saw horses. Next, remove both bottom end screws (you might need WD-40 to help loosen them up). Then, with a block of wood and hammer, gently knock off the bottom rail only just enough to allow you to slide the new guide in place. Hopefully that works for you.