there called M-DSB ASSASSIN helmets and they are made by DeltaSquadBoss http://www.thedentedhelmet.com/f23/m...w-maker-34737/
Yep it is an Assassin.
Here is mine
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M-DSB can get you hooked up with one. The guy who makes them has backed off of production a little because he has a real life too, but you should be able to get one easy enough. Look for the sale thread on the Mercs.
well they already ID'd it for you, but yeah... the assassin is one of the coolest buckets out there.