Extractor Tension Gauges- Helps you properly tune the extractor on your favorite semi-auto and eliminate extractor and feeding problems before they start. Machined brass gauges substitute for a case rim. Insert the gauge between the extractor and the breech face and measure the resistance required to pull the gauge free of the breech face with trigger pull scale. The trigger pull scale shows exact amount of rim tension. Clearly shows when your extractor need adjustment for the proper amount of tension. Double ended design allows two gauges one for 9mm/.38 Super and one for .40S&W/10mm and 45ACP. Set includes both gauges. Brass, 2" long Works for most semi-auto pistols with exposed extractors and open breech faces.