Wiefferink designs, processes, and manufactures flexible synthetic materials in plastic sheeting. It offers biogas products, such as biogas silos, flexible covers for biogas systems, and special manholes for biogas systems; air blown covers and silo covers; flexitanks for drinking water supply or to store drinking water in case of emergencies; storage bags manufactured from plastic sheeting for use as a buffer for sewage water and as a storage system for various liquids; and manure bags for storing manure. The company also offers foils that have various properties, including gas-tight or gas-permeable, bacteria-proof, and fire-proof.