• Semi-circular design allows use in16mm O.D. test tubes with round bottoms • Teflon PTFE coated • ALNICO V encapsulated magnet • 13.7mm wide. Per each SP Scienceware a division of SP Industries is home to Bel-Art and H-B Instrument brand products. Each brand has a proud heritage in the laboratory supply market and manufactures state-of-the-art laboratory equipment and biological drug manufacturing solutions that include market leading brands Genevac, Virtis, Hull, FTS systems and National-Hotpack. As part of a larger organization committed to science we look forward to increased opportunities to serve our customers and remain committed to developing, manufacturing and delivering innovative products, right in value. We appreciate your business and thank you for the opportunity you have given us.