it's value V ($450-500). If either side has a bird, its a T value ($350-400). If it says Thunderbird Hotel and has no bird, it's X value ($600-700) but infrequently trades. All 10 of the varieties are listed in TCR version 15 but a different numbering scheme is used from prior editions.

I've never seen one of the X rated chips. I wonder who generated that listing?