Angled aluminum bracket for hanging canoe seat below gunwales.  Commonly used on plastic and Royalex canoes and riveted between the gunwale and hull material.
Sold as each.  Need 2 to hang a seat.
Specify the depth of your seat.  Most seats are either 9.5", 10.25", or 11.5" from front to back.

These are L brackets that are between 6-7" tall (seat drop) with the L portion 1" wide (where seat mounts).  The width of the bracket is decided by the depth of your seat.  The top of the bracket is cut flat that you will need to cut at the custom angle of the gunwales on your canoe.  Generally the drop of a seat is between 3-4".