- Cylindrical bowl feeders Manufactured from ordinary or stainless steel. Optional inside coating. - Amphitheatre bowl feeders Manufactured from ordinary or stainless steel. Optional inside coating. - Conical bowl feeders Manufactured from ordinary or stainless steel. Optional inside coating. - Synthetic fibre bowl feeders The pitch, the number of turns and the shape of the helix track will be fabricated in accordance with the customer's specifications.