SLR Sentry 6 .625 Clamp On Adjustable Gas Block Titanium. 125 inch port opening. Metering screw and screw bore design allows repeatability and reliability only SLR has been able to deliver. Single tool click to adjust gas metering. Melonite finish 4140 Nexturn Swiss precision metering screw. Proprietary Alloy Flat Spring with 1400deg temper. Melonite finish 4140 detent plunger. USES STANDARD GAS TUBE. WORKS WITH ALL AR15/AR10 HANDGUARDS. Included Accessories: Tool roll pin and mounting screws Specifications for SLR Sentry 6 .625 Clamp On Adjustable Gas Block: Manufacturer: SLR Coating: Melonite QPQ Finish Gas Block Journal Size-Diameter: .625 in Gun Make: AR Platform Condition: New Gas System Type: Direct Impingement Features of SLR Sentry 6 .625 Clamp On Adjustable Gas Block: 15-position adjustability from 0 - .125 inch port opening. Metering screw and screw bore design allows repeatability and reliability only SLR has been able to deliver. Single tool click to adjust gas metering. Melonite finish 4140 Nexturn Swiss precision metering screw. Proprietary Alloy Flat Spring with 1400deg temper. Melonite finish 4140 detent plunger. USES STANDARD GAS TUBE. WORKS WITH ALL AR15/AR10 HANDGUARDS. Included Accessories: Tool roll pin and mounting screws Package Contents: SLR Sentry 6 .625 Clamp On Adjustable Gas Block SLR SA6-TI-C: Sentry 6 .625 Clamp On Adjustable Gas Block Titanium