... : natural gas4. Material: steel5. Origin: Zhejiang, China6. Model: SMB-lock cylinder7. Brand: Longda This series of cylinders are of Japanes ... , and with the treatment of chrome plating. The seal ring is imported. The following are some of this series' ... etc.3. Quality Certificates: ISO9001-2000, ISO9001-2008 Quality Assurance System, the USA UL. 4. Products covering hydraulic cylinders, pistons, ...