1. Show 4-digit number, support first number as letter

2. Can work with up to 200pcs 1-key call button or 3-key call button.

3. Show different service type with calling number and show time when its stand-by

4. Can store 20 calls and track the calls up and down.

5. Three reminder way: voice prompts, vibrator, and both voice and vibrator.

6. Receiving Distance: 400m in open area.

7. Rechargeable battery

8. DC 3.6V Frequency: 433MHZ

9. Working current: <10mA

10. Dimension: 53*39*16mm