Facilitating dilution and concentration studies, these racks streamline the transfer of samples between 0.2ml PCR tubes and 0.5ml, 1.5ml, and 2.0ml tubes. Their versatile design allows rotation and customization based on the end-user's specific application requirements. The racks feature tapered wells that securely suspend tubes, ensuring stability during studies, while also making tube removal effortless. With molded-in indexing, the racks provide a convenient system for easy retrieval of tubes, enhancing the overall efficiency of laboratory workflows.