This Extra Power Striker/Firing pin springs are a must for all 45 ACP, 45 GAP & 10mm Glocks. These bigger guns use 9% heavier firing pins but come with the lighter weaker 9mm firing pin springs which will eventually cause light primer strikes. These springs are also highly recommended for all other Glock models to insure positive primer strikes insuring that your pistol fires. These springs are better than the Glock springs. You will feel little or no difference in your trigger pull weight. This spring is manufactured by Ghost Inc.