Provides critical repeatable -1°C/minute cooling rate required for successful cell cryo preservation and recovery. Only requires isopropyl alcohol and mechanical freezer. Containers are labeled with graphic, step-by-step instructions. Vials are protected from alcohol contamination by a floating rigid insert. Withstands repeated freezing/thawing. Stackable. Container holds up to 18 x 1.2 or 2.0 ml cryogenic vials. Dia. x Ht: 8.6 x 11.7 cm.