Type explanation:HJW800-800-3.0 (HJ welded steel cylinder, W seam horizontal , 800 nominal diameter, 800 nominal volume, 3.0 nominal pressure) HJW600-400-3.0 (HJ welded steel cylinder, W seam horizontal , 600 nominal diameter, 400 nominal volume, 3.0 nominal pressure)superior of product:the B2-level ,with advanced equipment, high degree of automation and reliable technical quality