SLR Synergy Mini Compensator 5.56 1/2x28 Thread Black. No ports on bottom to reduce ground blast. .252 bore. 1.84 Overall Length. .862 Diameter. Works with VG6 CAGE Device. Adds 1.24 inches to Barrel Length. NOT for 14.5 inch Barrels. ALL NFA Rules Apply. Included Accessories: Crush Washer Specifications for SLR Synergy 5.56 Mini Compensator 1/2x28 Thread: Manufacturer: SLR Color: Black Caliber: 5.56x45mm NATO Finish: Melonite QPQ Fabric/Material: Stainless Steel Threads per Inch: 1/2x28 Included Accessories: Crush Washer Features of SLR Synergy 5.56 Mini Compensator 1/2x28 Thread: 1/2x28 Threading. No ports on bottom to reduce ground blast. .252 bore. 1.84 Overall Length. .862 Diameter. Works with VG6 CAGE Device. Adds 1.24 inches to Barrel Length. NOT for 14.5 inch Barrels. ALL NFA Rules Apply. Included Accessories: Crush Washer Package Contents: SLR Synergy 5.56 Mini Compensator 1/2x28 Thread SLR MD-556-MINICOMP: Synergy Mini Compensator 5.56 1/2x28 Thread Black