STOP, if you don't know what does what amongst all these controllers and alarms check out the Guide to Gordinier Alarms and Controllers located below. In a busy lab the last thing anyone needs to worry about is equipment function or malfunction. Princeton Cryo.com offers a variety of alarms to help keep your lab functioning smoothly. High and Low Level alarms keep you informed on the level of liquid nitrogen inside the freezers, while supply alarms will alert you when the LN2 supply is running low. We also carry alarms with built in shutoff devices to prevent freezer overflow.