Harbor Freight is going to be very upset when they get raided by the ATF for their stockpile of post-86 machinegun vises.
I hate to see this happen, but it is unfortunately a known risk when dealing with the ATF and their endless supply of zip ties and shoelaces.
The worst part is that no matter how many letters they send you to inform you that a certain device is legal, it only takes one letter that says it is no longer legal to wipe out all the others.