Key specifications/special features: Technical specifications: Outer diameter: 60-508mm Standards: api, sepc, 5ct Steel grades: h40, j55, k55, n80, l80, c90, c95, t95, p110, q125 Connection: stc, ltc, btc and premium connection Inspection: sgs, bv Certification: iso 9001: 2000 Delivery time: after received deposit 10-60 days according to the quantity Payment terms: t/t, 100% l/c at sight Port of shipment: xingang tianjin, shanghai port, guangdong port, ningbo port, qingdao port Quality control: Company has perfect quality assurance system, advanced testing equipment and high-qualified management team with control over series of activities such as contract signing, product research and development, productive process and test, product preservation and delivery.