Clippard MPA-3 Actuator

So, I'm finally considering trying one of these actuators in the pneumag i have here. But when I search for it, I usually see something like this:
http://www.airsoldier.com/mm5/graphi...ppardmpa-3.jpg

Even after finding some other pictures around the net, it seems impossible to get an idea of what/where this moving part/piston is that will be responsible for tripping the sear. Can anyone clue me in on whether this is included somewhere or if i need something else?
note: i'll be using a 3way solenoid with this ram/actuator.

you need a plunger and a ram like in the parts box compartment next to the LPR sleeper extension in tha top row, second compartment to the last on tha right:
http://i63.photobucket.com/albums/h1...SDC16839-1.jpg

You cut most of those visible threads off, or at least slot them for the sear if you want to use the edges for mounting (not common).

The plastic piston inside has center ring that you put the plunger into. Luke used to have those, which are little stainless steel cylinders cut to the right size. I think he uses those as bait to get you browsing his website.

That is the plunger assembly in 'reebs pic.

There's a fully assembled one in the top of the third from the right, middle row.