Currently no realistic and simple simulator devices exist that replicate normal or abnormal human capillary refill time - the time required to refill the pink coloration within the skin when pressure is applied. In our first phase, we will develop several prototypes of simulator devices through the Department of Emergency Medicine at USC, and test their realism with physicians at USC and CHLA. Then, we will validate their use using simulator-based drills with the Los Angeles Fire & EMS paramedics.