This is a pair of Integy Purple Aluminum Castor Blocks or C-Hubs for the HPI Savage X, XL, 21, 25, and Savage SS trucks.  These are also known as uprights.  These will work on the front or rear of the truck.  To upgrade both the front and rear, purchase a quantity of "2" packages.  These look great, and they are good replacement for a commonly broken part on the Savage truck.

INCLUDES:
Two aluminum castor blocks
Two 3x20mm cap head screws
Two 3mm nuts