What’s this Impact plenum

This doesn’t look like a stock mk11 plenum. It also looks a bit different to the large polish off set plenum. What do you think?

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It’s on Roelf’s gun from Airhunter in there lasted video. Shooting 30g slugs at 950fps with a 600mm barrel .. Also has the power dial on 2? 
It reminds me of car manufacturers trying to disguise there new models... why is there a cover above the plenum so you can’t see the barrel. 🧐
 
The hammer wheel setting doesn't tell much, being you can make it say what you want. By way of the adjustment screw, I can have it say 2 or MAX on the same exact tune.

When I got my Impact from Ernest, it was doing nearly max power on setting 2 if I remember correctly....could have been on C. I reset the wheel to MAX without changing the guns power level, just by reducing the length of the screw.

Seems this could be the answer for those who dont like the looks of the other external plenum.
 
It looks like he had a box made to hold extra plenum air. I've been working on prints for a similar plenum, one that matches the corners of the Impact's rear block and extends up to and actually mounts to the top rail. 

The benefits are twofold. First, there's a lot of plenum space available, more than can be used with just a larger tube. And the second being most beneficial. In having the box mounted to the top rail it prevents torqing and barrel p.o.i. shift when pulling on the pistol grip at the shot.
 
I saw that plenum here on the forum awhile back he made his own. Roelf's hammer setting of 2 could mean he has a hammer weight. Hammer weights really mess with your settings and ability to tune. With only a smallish weight I had to use an Allen and turn the hammer spring adjustment all the way down to so I would have a meaningful power dial. Bob-O also explained what could be going on. The cover above the plenum that hides the barrel is an available aftermarket add on.
 
My bet...an FX Proto or a DIY

0.35 cal will have all the power upgrades available, including a larger plenum (no doubt about it). Probably will be close to the SilverSurfer power ;), the big Q is when?. I have been asked that a lot ... but no one knows. For the ones looking for stock power, wait until that one comes, but careful new things usually comes with new problems. (But I like/love to solve problems).

Do not forget, Matt D. Works for FX and this guys are close friends and have a direct line with FX.