The blue Eppendorf® IsoPack for 1.5/2.0mL PCR tubes is a cool pack designed for use with the Eppendorf® IsoTherm system. The IsoTherm system can be used to prevent enzymes from becoming inactive as well as for PCR sample preparation, sample transport and slow thawing of frozen samples. The blue IsoPack will maintain -21°C for up to 3 hours. For Tube Size: 1.5/2.0mL. Color: Blue. Eppendorf® #: 022510223.