Seat Reinforcement Plate for all 1979-1993 Mustangs.
This reinforcement metal plate mounts under the floor pan behind the front seat to strengthen the seat mounting area. This area typically tears under stress from hard acceleration.
I wish this was around 16 years ago when I bought my '83 GT. The floor pan was torn bad at the left corner of the driver seat. I welded in a 16 gauge plate back then but this would have been much better. Well worth the money.