This is an electret condenser micorphone in a pen cap for inconspicuous recording.

This niniature microphone is designed to provide that inconspicuous look coupled with excellent performance. Its omni0directional pick-up patternis ideal for all types of applications. 

Specifications
- Built-in power supply requires an A76 battery.
- Electret condenser with F.E.T. circuit.
- Omni-directional
- 50 Hz to 18,000 Hz
- Sensitivity: -52 db
- Impedance: 1000 ohms
- Cable length: ~20 feet