This is a pair of Aluminum Front Caster Blocks for PRO-2 SC and Slash® 2WD. Pro-Line has just released a new must-have upgrade for the PRO-2 and 2WD Slash®: Blue Aluminum Caster Blocks!The super strong Blue Anodized Aluminum Caster Blocks with Pro-Line logos add durability and prevent the King Pin from bending and popping out of place. Upgrade your PRO-2 SC or Slash® 2WD Truck Today!