Transforming the backpack is easy, as is attaching it to Prime’s back. It’s done with a spring clamp on the back. Pretty easy.
Having Prime hold the cannon grips aren’t enough to keep it in place, you have to plug the connectors into arms in the backpack. The connectors themselves are made of soft plastic.
This version of Prime no longer has the forearm swords.
Prime’s guns are stored in the backpack.
Comparison with Buster Optimus Prime
Comparison with Ultimate, Jetwing, and Jetfire Optimus Primes.
Jetwing parts on Buster Optimus Prime