Gatco - Flat Bottom Bins
From GrainAir Tubes
GrainAir Tubes work to cool your flat bottom bins and won't interfere with your clean out operation either. By using a retractable base the system allows you to support the roof ring and GrainAir Tube while unloading. When you wish you do your final clean out, simply loosen the base set screw and retract the base into the GrainAir Tube, and out of the way of your sweep or vac.