The blocks for use in heaters and dry baths have a variety of well quantities to process numerous samples at once. Models safely hold test tubes, microcentrifuge tubes, vials, conical-bottom centrifuge tubes, or PCR plates, tubes and strips in close contact during the heating process for ideal heat transference. Constructed from solid, anodized aluminum, the blocks offer maximum heat retention. Interchangeable, modular blocks mix samples and may support thermometer use for easy monitoring of conditions.