You spray it through the throttle body so it will clean manifold along the way.
I compared it to Seafoam and found Seafoam didn’t do much in my manifold.
We don’t get amsoil power foam in Canada.
Seafoam didn't clean my manifold too (there were some other cleaning effects, just not the manifold for sure), after two uses and reading on the forum, seems like it's out dated compared to the others.
Seafoam and CRC costs way more than Amsoil, Redline, and Techron where I am located so I will be trying Amsoil Power Foam next time around (the later three has official distributors and prices are comparable to U.S. retail prices, Seafoam and CRC costs twice as much).