Like I said, I think the company went out of business some years ago.
What they were was a Match grade, fully adjustable trigger unit for people who were shooting slugs for high level long range accuracy.
They also made them for the Remington rifles that used the same basic trigger unit.
As far as I know, these were the only actual steel trigger guard units ever made for the Remington 870.
The plastic units do seem to take heavy blows better. While the aluminum guards will break, the plastic bends, flexes, and tends to return to shape enough that the gun will still work.