Interruptions during compressions during (CPR) can decrease the survival rate. The chest compression fraction (CCF) is the amount of time spent administering chest compressions during cardiac arrest. If you can obtain a CCF above 80% you can dramatically increase the survival rate. The CCF timer App works in conjunction with a compression rate of at least 100/min. We have also added a metronome to the App. You can select 100 or 120 beats per minute. This is a great application to use in your next CPR training class. Instructors are currently using our CCF app with their students during multiple rescuer training. Students can split up the following rolls: Compressions, rescue breathing, AED operator and use of our chest compression fraction timer App. This will allow the students to see their chest compression fraction timing. Students can also share their results with friends! This App is to be used for training only. Thank you! DART Sim Inc.