... is one of the top level wellhead christmas tree manufacturers and suppliers,Website:http://www.zztopdownhole.com, ... Consist of casing head, tubing head and Christmas tree -Applicable to all the casing and tubing programs ... (hydraulic) safety valve Specification of the X-tree Working pressure (psi) 2M, 3M, 5M, 10M, 15M ... , 20K Material class AA, BB, CC, DD, EE, FF Working temp. L, P, R, ...