Ive been around for more than two Decades in this hobby, and can say Ive never seen or heard of them. May be a Flea market branded sub. Have you pulled one out and checked out the information on the magnet if to see any information on it yet? May help posting a pic of that
Used (normal wear), I am selling my 2 12in megaloud subs with the box and also a 600 watt amp. I bought these subs and amp from stealth audio. These things slam. I believe one sub has a lose wire or might be blown not to sure. . Make an offer!;
offerup.com
There is a guy on FB listed a pair recently, $100 a pair seems to be the prevailing rate.