RFF type out-feeders are designed for the automatic emptying of silos with a conical bottom. The out-feeder is used to remove dry, fine material with dimensions of max. 13x13x13 mm, which does not contain foreign bodies. The material must not cause any corrosion, therefore its moisture content may not exceed 25% of the total specific gravity. The out-feeders are used for silos with a maximum diameter of 4m and height of 12m. The material can be fed in various directions, to one or two screw conveyors.