UTG Pro A2 Receiver Extension Tube Kit Matte Black Anodized 6061-T6 Aluminum Black. UTG A2 Receiver Extension Tube Kit Includes Rifle-length Extension Tube Buffer and Spring A2 Spacer and Stock Screw Tube Constructed from 6061-T6 Aluminum and Finished in a Matte Black Anodization Specifications for Leapers UTG A2 Receiver Extension Tube Kit: Manufacturer: UTG Pro Color: Black Finish: Matte Black Anodized Fabric/Material: 6061-T6 Aluminum Gun Make: AR Platform Gun Type: Rifle Package Contents: Leapers UTG A2 Receiver Extension Tube Kit UTG Pro TLT-A2KT: A2 Receiver Extension Tube Kit Matte Black Anodized 6061-T6 Aluminum Black