Bottle connector 1/4" x H21,8-14 with left hand thread

Code according to CASTEL: 7156/2 LH
Reducing nut for new refrigerants R32 and R1234yf. 1/4 "SAE external thread allows the connection of a hose to fill the cooling system with a cylinder containing a refrigerant equipped with a threaded connection W 22.8 x 14. The nut is provided with a perfectly matched, durable gasket. Due to various properties and safety requirements in cylinders of R32 and R11234yf