The 6BN6 is a 7-pin miniature gated-beam pentode specifically engineered for FM sound detector, limiter, and audio driver service in television receivers and FM broadcast tuners. Operating on unique electron-optic principles, it features a sharp-cutoff limiting characteristic that removes amplitude modulation noise without requiring separate limiter stages or transformer tuning. Operates on a 6.3V heater and fits standard 7-pin miniature sockets. Available NOS and tested used.