Blue Microphones Bottle Tube Microphone System with B6 The ultimate in hand-built craftsmanship Class A discrete amplifier circuit with hand-selected EF86 pentode vacuum tube in triode mode Mic system-allows for various capsules to be swapped "on the fly" for maximum versatility Hand tuned and tested Includes B6 capsule, our renowned 9610 Tube Power Supply, Champagne tube mic cable, and ATA flight case