They are made of PPFV, this polypropylene contains 20 borosilicate glass fibres type "C" resistant to chemical agents. It has a very good mechanical strength, high dimensional stability, can be easily stored and withstands temperatures up to 100°C. Its resistance to UV radiation is enhanced by the addition of carbon pigments and UV stabilisers. An anti-rust additive improves its resistance to oxidising chemicals. With EPDM or FPM (Viton) seal and locknut. In case of use with high acid concentrations, please ask for specific references with FPM (Viton) seal.