Vehicle mode: It is the typical Prime truck we all know, but it has some extra things. Unlike the Machine Wars Prime, the cab CAN turn independently from trailer so now you can drive like the real thing. The trailer has two door's at the back where you can put the nebulon and the large Prime head. Overall a great truck!
 
Transformation: Powermaster Optimus Prime can turn into four things.
1# a truck
2# a robot
3# a battlestation
4# a large verion of Optimus Prime
 
It is easy to transform the cab to Prime. Just basic transforming, exept one thing.  For Prime to Transform you need to put the nebulon (little robot man/engine) into Primes radiator grill. If you don't do that, you can't transform him.  Many kids have gotten rid of this function by forgetting to put the nebulon in and breaking so hard that the peace of plastic that prevents Prime from  transforming breaks. And that's too bad. It must hurt for Prime to be injured that way.
 
Making him into a battlestation is pretty easy, just don't break to hard before you  see why the parts are not moving. Many places you have to turn one part to get another free.
 
Making him into a large robot is very easy. Just make Prime into a cab, lift the back part up so he becomes a square. Put the square into the trailers square compartment, and put the large Prime head on. The trailer is of course put down on it's back part (where the door's are) so it becomes a body.
 
Weapons: Two large turrets and two large black cannon-guns.
 
Other notes: THIS IS ONE COOL PRIME!
 
Overall: Optimus Prime has many shapes and forms with all the figures that are made of him. The Powermaster edition is a really good figure. Prime looks like he could throw Megatron across the galaxy in his large robot (Powermaster mode) form.
 
On a scale of one to ten this toy gets a 9