Aegis Scientific offers as an option to our refrigerators the AS-1 or AS-2 alarm. The AS-1 alarm is a single probe alarm. The AS-2 alarm is a tri probe alarm. There are 2 probes for product, 1 upper and 1 lower and a probe for air temperature. The probes which simulate product temperature are placed in a glycerine bottle. The alarms are audible and visual, have a digital display, battery back up and remote contact