This is a pair of inner door belt weatherstripping for the driver's side and passenger side of your 1994-2004 Mustang. Inside door belt weatherstrip attaches to the top edge of the inside door panel. This weatherstripping helps keep debris clear from inside the door panel.
I have been ordering items from Latemodel Restoration for many years. I've found them to be exceptionally professional, timely with order processing and shipping correct items ordered. I've never received an incorrect item on an order.