1. Li-ion battery operated with AC adaptor charge equipped. Operating time > 90 minutes. 
2. 3 sides or 4 sides display, good view for audience from all direction. 
3. LED digit height 5.8cm(2.3”), 2 digits, color red. 
4. Size:15cm x 15cm x 20cm(height include handle), weight 2Kg. 
5. 60 seconds time out display, 1~99 seconds preset time out(option). 
6. Flashing left corner dot LED when not used. 
7. Easy to use: Push to start, push to stop, double push will blank LED. 
8. Power switch & preset thumb wheel located at bottom(Option). 
9. Good for many kinds of game like basket ball, volley ball, tennis & table tennis.