Shade robes are a rare drop from shades. Their only stat is +4 bonus to prayer, which is equal to the bonus provided by the widely-available monk robe bottom. Because of this, and the difficulty involved in killing Shades, the robes may be criticized by some players. However, others may wish to obtain the robes to complete a collection, or for aesthetic purposes.
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.