TONG Flow Systems (SUNSFLOW). is one of the main suppliers in China manufacturing and supplying of advanced pipe systems and solutions, connecting people with water and energy. Our main pipeline system product are as below: ductile iron pipe, ductile iron pipe fitting, manhole cover, gate valve, butterfly valve, check valve, Y strainer, flange, dismantling joint, flange adaptor, flexible coupling, saddle, gibault joint and repair clamp.