The Pure Classic is a transducer-only system. No battery, no onboard electronics, just the pure pickups. Don"t be fooled by the sound of some competitors" "thin sounding" passive systems. The Pure Systems are definitely different. They sound full and rich and have sufficient output to drive most amps and PA systems directly, without a preamp! Advantages of the Pure Guitar System The special Pure surface transducers transmit a significant portion of the soundboard because they are not as close to the strings as an under-saddle pickup. Each of the 4 transducers is designed to pick up a specific string pair, but also "listens" to the adjacent area around the bridge. The Pure pickups are not under pressure and therefore do NOT sound percussive or harsh. The Pure System reproduces all strings nicely balanced, a known problem with under-saddle pickups. Unlike under-saddle pickups which passively can sound thin and trebley, the passive PURE system puts out a nicely balanced, warm, full range signal. The Pure Classic includes four high quality transducer pickups, to allow even distribution around the center brace found on most nylon string guitars. If you do not have a center brace, consider using the Pure Mini pickup system instead.