Teachers go hi-tech to keep pupils' attention
http://www.post-gazette.com/neigh_north/20020529nsoundfield0529p7.asp

URmic Infrared Amplification Classroom System
Model: IR-6600

Included:
1. Amplifier
2. Infrared handheld(or headset) microphone x 2
3. Infrared receiver x 2
4. Sensor
5. Wall mounted Case with lock

Specification:
- Channel: Dual Channels
- Graphic Equalizer: 7 bands
- Audio Inputs: Computer/TV/VCR/DVD player/CD player
- MIC IN: Connect the wire microphone or other infrared receivers
- Sensor input jack: F connector for sensor connection
- Output: 8 ohm 20W x 4 Speakers
- Use Control: 1. Channel A & Channel B Volume 
                        2. Microphone Volume
                        3. Computer Volume
                        4. TV / VCR Volume
                        5. CD / DVD Volume
                        6. Line out Volume

Size: 44 x 22.5 x 5.2 (cm)
Weight: 3 Kgs