Block holds twenty 12mm or 13mm test tubes for Benchmark Digital Dry Bath (BSH1001, BSH1002, BSH1004). Block cavities are precision machined to match the conical shape of the tube size, providing unsurpassed temperature uniformity. Block size: 3 x 3.75 x 2 inches (7.6 x 9.5 x 5cm). Capacity: 20 test tubes. Tube size: 12mm to 13mm. Material: high grade aluminum. Sold individually. Benchmark Scientific #: BSW1213.