Charles Ross & Son Co. offers Ribbon blenders. All units are direct driven by an inverter-ready gearmotor and variable frequency drives are usually supplied with the Ribbon blenders for soft start and agitator speed control. Standard models as long as 1,000 cu. ft. are offered, with larger capacities available by special order. The model 42NSD features a discharge screw positioned across the entire length of the trough, which is powered by a separate, direct-drive system for independent speed control.