This listing is for ONEAction Retarder or Piston Buffer for an Akkar or Charles Daly 600 series semi automatic 12 gauge shotgun. These will work on both older model and recent production Akkar 12 gauge 600 autos. They will Not work in 635 series 3 1/2 inch shotguns, only for the 12 gauge 3 inch. Manufacturer is a Tennessee Polymer Company. These are identical to the factory Akkar buffers, except for coloration and coating. It is a no go won't work item for the 635 Mag that is chambered for 3 1/2 inch shells. Construction is injection molded polymer. Finish is flat black coating. Schematic number is View 48, Piston Buffer or Action retarder. Dimensions are 1.255 inches overall length; 1.024 inches inside diameter; and 1.40 inches outside diameter. These Action Retarders or Piston Buffers will only fit a Akkar model 600, or an Akkar / Charles Daly model 600 Semi Automatic shotgun chambered in 12 gauge.