The CNC 9mm Glue Tabs are just that. They are machined out of solid polycarbonate rod.. The is a superior manufacturing method, while more expensive than injection molding, a stronger more reliable tab is possible. The CNC 9mm tabs are a center pull tab that can stand up to slide hammer work better that injected molding. No air bubbles, rough seams or flaws. Comes 4 tabs per pack. Make sure you pick up some Euro-Spec PDR Glue to go with your CNC 9mm Tabs.