Our product has unique electronic compression depth and frequency detector.

1. First right operation: the 4 indicate light on the left shoulder will be on.
2. The lights off: lack of battery or operation mistake
3. When start the operation, a yellow and green light will be off.

• Red light: Press frequency 0-60 beats/min
• Yellow light: Press frequency 60-80 beats/min
• Green light: Press frequency 80-100 beats/min

1) Right operation: 2 green lights on Press frequency >100 beats/min

2) Red light flashing: compression depth insufficient