SS G Hammer SetHighlighted featuresPrecision CNC machined Stainless SteelMAF Polishing Technology for greatly smoother operationDurable construction prevents warping under hard useHammer set including hammer, sear & firing pinFor TM G17 Gen3 and Gen4 & G19 Gen3 and Gen4**Important Notice**It may has a condition that your pistol cannot feed the BB bullet due to lightweight gas supply. You just simple remove a spacer to solve the issue. Alternatively, you may consult your gunsmith for advancing fitting to solve this issue as well. Increasing in FPS can be achieved; however, it may require other parts to collaborate and advanced skill is needed. improper installation / fitting can shorten the life of the product.