Chill rack for microcentrifuge tubes changes color as the temperature rises above 7°C. To use, simply pre-chill the rack at -20°, move it to your bench, and add your tubes. The rack slowly warms, taking approximately 4 hours before there is a complete color change. Each ArcticIce® MCT holds 24 tubes in a 6x4 array and will hold conical and skirted 1.5, 2.0, or 0.5 mL tubes. (Not for use with cryogenic tubes.) Includes a clear lid with stacking rim. Measures 146 mm L x 105 mm W x 70 mm H.