Equip Optimus Prime with the six parts of the Gravity Armor!  Gravity, the Micron with the power to manipulate gravity, comes with a joint that allows him to be combined with TAV50 Hyper Surge Optimus Prime!  

Gravity is about 5cm tall, and Optimus Prime is about 11cm tall.

TAV41 Gravity & Optimus Prime With Gravity Armor