The Radian XL according to a review on this site states it uses 12x4 prop. You may have to search to see if you can find a 12x4 folder including a motor shaft adapter. You will have to measure the diameter of the motor shaft so get the right hub. If you are lucky it may also have a spinner and if you very lucky is may be the right size.
The XL with no spinner will look odd but will still fly perfectly well.