I suspect that what you got was destin to be an advance replacement for someone who had a dead esc and they sent out the new one and a envelpoe to mail the dead one back in.
That is what they did for mine. I called in about my problem & they sent a new MMM & the mailer for me to return the dead one.
I have bought 2 MMM v2s recently and neither came with the mailer. I suspect that it is for people to return their dead esc...
Glad to hear that you like the CC escs Shawn. I have about 2 dozen CC escs (various types) and have had great success with all of them. I knocked the caps off one MM, and may have damaged another. I have always had great service from CC.