Our Magnetic Stir Bars are constructed of high quality magnets coated with PTFE. Along with individual sizes of polygon, octagon, and egg-shaped, two convenient assortments are available. Stir Bar retrievers also available. Additional Info: Magnetic Stir Bar Assortment, Set Of 50 Package Size(L x W x H): 4 X 4 X 1.5 (IN) Categories: Hot Plate & Stirrer Accessories, Stir Bars HTS Code: 8505.11.0000 UNSPSC: 4.11224e+007 Country Of Origin: INDIA