... BEST price BEST quanlity BEST service zhejiang zhongde industrial co.,ltd. was professinal the upvc pipes .it have 13 years old ... fittings can be made, according and conforming to the following international standards:1) American standard (ASTM Sch 40 & Sch 80, SDR ... standard (GB 10002, GB 5836, GB 14823, GB 13664)7) International standard (ISO 4422, ISO 3633, IEC 614, GY 30 pvc ...