Not that hard, the clear washer needs to be filed down to fit down the switch tube, its diameter is slightly to big. The switch fits right in. The lighted switch doesn’t do momentary on its a momentary off. I’m pretty sure while I was installing the last one that the original switch would fit on the lighted switch board, if you wanted to exchange switches to gain momentary on back. KD has the clear 14mm x 8mm silicone tailcaps, make sure you order the transparent. The silicone stud in the middle of the tailcap will have to be trimmed with a razor 2 or 3 mm to keep pressure off the switch button when assembled, otherwise the switch will always have pressure on it and be in the on state with a momentary on.