TP9SFX Spring Options

These are the springs that I have used and tested. Your mileage may vary based on your ammo load. 

1. Wolff Cold Commander - 13LB: item 42213, 14lb: Item 42214 & 15lb item 42215
https://www.gunsprings.com/COLT/COMMANDER%20SERIES%20PISTOL/cID1/mID1/dID2