hi michelle,
are you looking for a diffuser tip (cone), diffuser cap (hatch), or a diffuser lens?
And please measure the diameter of your light in milimeters. The Fenix LD20 set the standard with 21.5mm heads (up to 21.8mm), and many followed this example (Xeno E03, ..). Quarks have a 22.0mm head so the Fenix diffusers require some grinding.