24-Well Metal Rack for 2ml Centrifuge Tubes manufactured by Bioland Scientific, LLC. can accodomate 2ml centrifuge tubes and keep them in cold after fully refrigerated or leave on ice. After being fully refrigerated (-20℃ for 4-6h), the Metal Rack can keep low temperature for 1-2 hours. It is used with a silica gel base to ensure a longer cooling time.