- This product is VAV Series made of EPDM material and is suitable to drinking water .- Rust is not generated because this product is produced with special epoxy heat-treatment paintng. - The bladder separates gas from liquid to prevent water contamination. - The maintenance cost is low because the bladder may be replaced. - As the bladder and the inside wall of the tank do not contact, damage caused by friction may be avoided. - Water hammering is prevented to avoid possible damage of the pump and pipes