I have a few SiCo products and used their slotted piston which caused a little too much blowback. Not so with this one, it looks great and performs even better. And on top of that, the price that is offered from this site is the best I could find on the internet, and free shipping. Others may have been around the same price but it cost you $5 to $10 for shipping, not here. If there’s any SiCo or I believe Griffin may use a slotted piston, make the switch and buy from here.