Only the best products in the industry have been selected for this kit. These top ends were designed and tested using a MIL SPEC lower receiver with a Hahn 9mm Magazine Adapter and a Standard Hammer. Forged 7075-T6 Aluminum YHM Flat Top Upper Receiver "T" Marked Upper Receiver Forward Assist Installed CMMG Ramped 9mm Bolt Carrier Assembly (YHM-921-A) 16" Steel Barrel, Heat Treated to RC 25-32, Melonite Finish, Threaded 1/2"-36 Chambered in 9X19mm, with a 1:14", 6 groove Twist YHM 9mm 5C2 Flash Hider / Compensator (YHM-80-5C2) YHM Carbine Length Handguard (YHM-9645) YHM Single Rail Gas Block (YHM-9385-A) Hahn Precision Magazine Adapter (YHM-920) YHM extended Heavyweight 9MM Buffer (YHM-925-A) Metalform 32 Round 9MM Magazine (MAG-9MM32)