1. Irw-89m can be used for 6 hours under the full charge.
2. You can speak in natural voice.
3. The handheld microphone features four selectable frequencies.
4. More than two infrared microphones can be used at the same place at the same time.
5. It is a good tool for teaching, singing or speaking.
1. 2.08 MHz-etc. 2. FM. 3. 32.768 KHz. 4. 15 KHz. 5. 50μs. 6. 850 nm. 7. 360°. 8. 200mA/2.4V. 9. 15M min. 10. Dynamic. 11. Rechargeable NiMH. 12. 2300 ma x 2. 13. About 8 hours "fullcharge". 14. 248(L). 15. 260g.