Our stainless steel 9mm/38 Super ACP Billet Steel Slide Stop is CNC Machined from billet alloy steel and heat treated to RC 40-46. The shaft diameter is .198"-.199". Our Billet slide stop will replace your MIM or cast slide stop with a much stronger part, greatly reducing the chance of breakage of this critical part. Life time warranty against breakage to the original purchaser on unmodified part.