FRIO-Temp High Precision Liquid-In-Glass Verification ThermometersHigh Precision Liquid In Glass Verification Thermometers FRIO Temp verification thermometers for sample temperature measurement within Freezers, Refrigerators, Incubators or Ovens without introducing contamination. Features These thermometers are: filled with environmentally safe non toxic, non hazardous, biodegradable Enviro Safe liquid EnviroKleen certified by ChemTel, an independent laboratory (except H B Catalog No. 20630 Organic liquid filled)