Shade robes are a somewhat rare drop from shades. Although they look transparent whilst on a Shade, they are not transparent when worn. Their only bonus is a +5 Prayer bonus, which may be criticized by players because of how hard it is to obtain them compared to the superior Monk's robes. However, when compared to how difficult it was to acquire these robes in the past (a rare random event occurred, but the drop was random and gave either the top or bottom), obtaining them now is arguably a simple task.
Before an update, these robes were tradeable. They were most likely made untradeable due to the fact that people were being tricked into believing they were ghostly robes, since shades who had dropped them were transparent.