These are a set of 4 plastic replacement drive hubs for your TXT.  These are designed to allow for the use of EITHER the Clodbuster or TXT wheels.  These are a direct fit on your TXT-1/2 axles and accept the stock 12mm brass drive hex.  

Note:  These will not work on a Clodbuster/Bullhead axle due to their shorter outer axle length.  Use CPE-HUBCLOD if using Clodbuster/Bullhead outer axles.