- Small Backstrap
- Medium Backstrap
- Large Backstrap w/ Beavertail
- Backstrap Retaining Pin
FN 509M Backstrap Set, Black. Enhance your FN 509 Midsize pistol with this backstrap set constructed of durable black polymer. This factory original set comes with a small and medium backstrap along with a large strap with a beavertail design. Also included in this FN 509M backstrap set is a steel backstrap retaining pin for quick and easy installation of your 509M grip. These straps are made to the same high standards as you would find in the other parts of your 509M and are built to provide both comfort and a more positive grip.