Individually serialized, these oven thermometers contain red organic liquid against white back glass. partial immersion versions feature a round glass swell to hold the thermometer in place b60803-0600, b60803-0800, b60803-1000 and b60803-1200 feature pfa safety coating to keep liquid and glass encapsulated in the event of breakageshould you require an individual thermometer calibration report, factory calibrated thermometers or custom calibration services are available.