BF 504 is a dynamic cardioid instrument microphone from the Black Fire series, intended for close-miking drums and percussion (e.g., toms and snare) and also suitable for other instruments. It shares core specifications with the Sennheiser e 604: 40 Hz–18 kHz, 350 Ω nominal impedance, 60 g weight, Ø 33 mm × 59 mm, XLR-3 output, and over 25 dB front-to-back rejection at 1 kHz. Includes a drum clip for mounting.