9686-1 (Inv) Simple and Motorized Mechanisms Base Set (Simple & Powered Machines Set) 388 Parts, 2 Minifigures, 1 Book, 5 Gear, 2009 Sets: Educational & Dacta: Technic
* Add 1 Part 62821b Dark Bluish Gray Technic, Gear Differential with Inner Tabs and Closed Center, 28 Bevel Teeth (Alternate) (match ID 1)
* Change 1 Part Dark Bluish Gray 62821a Technic, Gear Differential with Inner Tabs and Open Center, 28 Bevel Teeth {Regular to Alternate} {match ID 0 to 1}