The 2 locking diff. pcs. are worth it already. They can be used for Tamiya trailor trucks and is where i installed them. For CC01 or XC owner get another set to lock the front diff., makes a big difference with all 4 wheels spinning.
These parts are great for spares, or even those who want the extra diff lockers to fully lock both diffs for extra traction. The CC-01 is an offroad vehicle, so rocks and dust will eventually get into the gears, meaning that they will need replacement. As these are not common on other retailers' sites, RC Mart stocking them is a godsend! They are of premium Tamiya quality, and come with the complete set of gears, so that you can replace all gears, be it for a runner or a restoration project. The diff lockers included are also some of the best, most effective diff lockers that you can find for Tamiya diffs, short of using a racing spool. Awesome product!