These are deer antler sets with the skull plate. The large and XL generally have a larger spread, so even though they may have the same number of points as a smaller rack, they are bigger overall.
Most of these antlers come from white tail deer from Ohio, where the deer were killed by sportsmen. Usually the meat is eaten by the family of the hunter.
White tail deer are not an endangered species.
Not for sale in most southeastern states due to state regulations. It was confirmed by USFWS on October 15, 2015 that it is okay to sell white tail deer antler to California because the species is not native to that state.