Cloak Industries A5 Buffer Tube Black. If your MFR56 belt fed upper receiver needs more buffer options for your use case the A5 buffer tube is the perfect upgrade. This buffer tube also possesses 9 positions of stock adjustability compared to our Carbine Buffer Tube which only allows 6. Specifications for Cloak Industries A5 Buffer Tube: Manufacturer: Cloak Industries Color: Black Package Contents: Cloak Industries A5 Buffer Tube Cloak Industries CLK-A5BT-BLK: A5 Buffer Tube Black