The PRESTAN AED UltraTrainer is our most compact, lightweight AED trainer solution with full customization options to accommodate any classroom training situation. This AED trainer resembles a live training experience like no other on the market. Product Features PRESTAN is the First and Only Universal AED Trainer with the following: Dual Graphic (Adult/Child) Training Pads Pad Sensing System Preconnected Pads Child Training Button Child AED-specific voice prompts Automatic or Semi-Automatic shock simulation CPR Coaching, “Give Breaths” voice prompt Turn on or off compression metronome Turn on or off “Give Breaths” prompts Low Battery warning Use 3 pieces of C batteries Manufactured and assembled in the USA Additional features: Two languages AHA Guidelines Compliant and Upgradable Play/Pause Button 5 Training Scenarios Additional Details: How to toggle between 15:2 and 30:2 compression-ventilation ratio: Step 1: Hold the child button and power the button down at the same time. The unit will then beep. Step 2: Release both buttons at the same time. Step 3: Push the child button to select your preferred option (15:2 or 30:2). Step 4: After selecting your preferred option, power the unit off. Step 5: Turn the unit back on and you’re ready to train.