Training for emergency situations with the HeartStart Onsite AED just got easier. The Philips HeartStart OnSite (HS1) Trainer (M5085A) simulates how the OnSite operates during a real-life sudden cardiac arrest event. The HeartStart trainer comes with 8 preconfigured scenarios. Clear, confident voice instructions provide easy-to-follow directions to help responders acquire and demonstrate the basic skills necessary to use the HeartStart OnSite in an emergency. The included software is consistent with AHA G2010 Guidelines. The Trainer requires 4 "AA" batteries, which are not included.