... structure and transferring water and gas. UL certs Steel tube,including ERW and Seamless, round and rectangular or ... , Wall thickness:1mm---20mm. PURPOSE: fence tube, structural tube, scaffolding tube, water transferring tube, oil pipe, casing pipe, sprinkler fire ... fighting system tube (with groove available), furniture tube and so onCERTIFICATE: ISO9001, UL, FM, ...