The Blue B3 Mid-Size Diaphragm Bottle Cap is an interchangeable capsule for the Blue Bottle studio microphone. A variety of interchangeable capsules are available; each with its own frequency, tonal and pickup pattern characteristic. The B3 is a mid-size diaphragm condenser capsule with a cardioid polar pattern and a neutral, transparent audio quality.

Suggested applications for this capsule include vocals, distant miking of orchestral groups and instruments, banjo, mandolin, resonator guitar, jazz guitar, distorted electric guitar, electric bass, and much more.