Anodized aluminum heating block provides excellent heat transfer to your test tubes for maximum uniformity and reliable results. Baked-on enamel finish resists harsh chemicals and hard usage. Versatile operating range of ambient +5°C to 60°C (± 0.5°C). Just dial in the desired temperature. No need to unplug; designed for continuous use. Test tubes and cuvettes stay dry during incubations to eliminate mess and contamination H1208-1/-2 has a cradle design that permits tube rocking for sample agitation as well as numbered wells allowing for easy test tube identification. Also, clear acrylic side windows permit observation of colorimetric changes. H1208-3 is a straightforward design that is a simple block unit that has a 40-tube capacity (12mm tube size). 120V.