Schmid Tool is the mil-spec. That's pretty much it. They are the supplier for all the big guys in the industry and have been doing it for decades. That "S" forging mark is a guarantee of quality.

• Properly cast from 8620 steel
• Precision ground for smooth function and a perfect fit
• Phosphate coated for durability and corrosion resistance
• Fits all mil-spec dimensioned AR15 lower receivers