Building materials (non-metallic) in this class; building products (non-metallic) in this class; non-metallic forming aids and forms, including non-metallic forms for use in casting concrete; non-metallic expansion joints, including non-metallic expansion joints for placement between concrete slabs; bar chairs, profiles and other devices, all being made primarily of non-metallic materials, and all being primarily for the purpose of providing support for reinforcing materials to be retained within cast concrete