Two Elastic Bands securely fasten various sample vessels to the Recessed Platform (Part No. 7404-3900). Two bands are included in the Large Sample Set (Model H302, Part No. 7404-3020) for use with the Vortex-Genie 2 family of mixers and the Vortex-Genie Pulse. Sample vessels of up to 500ml can be used as well as microplates.