rectangular tube square steel pipe 1. Specification: 16*16-600*600mm 2. Thickness: 0.5-40mm 3. Standard: Can be required 4. All kinds of specification 5. Good quality with competitive price 6. Packing: Standard export packing The company can produce various sizes of longitudinally and spirally welded steel pipes according to the following standars such as API ASTM JIS BS DIN and GB etc.