Wawcon grit screw systems are usually all stainless steel with the exception of the drive unit. These units are all built with a commitment to quality and long service with easily replaceable components such as the lower bearing.
This picture is of an all stainless steel grit screw in a stainless housing, with a cyclone above it and a climber type bar screen with a belt conveyor, located behind the grit screw. These have all been in service for over 16 years. Please click on image for larger view.