As you know, iRO has two garment costumes - Archangel Wing and Rudra's Grace, and both of them can be enchanted with ASPD stone.
I saw many times people to place a trade chat "Rudra's Grace + Xm zeny -> AAWing" which made me think that there is some advantage to use AAWing over Rudra's Grace. I checked their descriptions and yes, there was a difference, costume version of AAWing is supposed to have 18 def. I bought it, equipped and... nothing, at least no numbers changed in status screen.
1) Is is a mistake in description and C. AAWing doesn't provide any defense (was defense value a leftover from non-costume version?)? If yes, is there any difference between these costumes, except of their appearance? Why people were willing to trade Rudra's Grace with additional zeny to get C. AAWing (I don't recall ever seeing it backward, to add money to AAWing to get Rudra's Grace)?
2) Several times I saw people to specify that they need ASPD stone for Rudra's Grace or for AAWing. Does ASPD stone has several versions where only specific one can be used for specific garment costume?