Tube Holder holds six 50mL six 15mL and twelve microtubes vertically. Holder snaps on to any Vortex-Genie 2 product and the Vortex-Genie Pulse. No additional attachment necessary For Use With SI-0236 SI-0246 SI-0256 SI-0266 SI-0276 SI-A536 SI-A546 SI-T236 SI-T246 SI-A236 SI-A246 SI-P236 SI-P246 Manufacturers Warranty Length 30 days