Explanatory notes
… valves 8481.20 ‑ Valves for oleohydraulic or pneumatic transmissions 8481.30 ‑ Check (nonreturn) valves … or closing an aperture (e.g., gate, disc, ball, plug, needle or diaphragm). They may be operated by hand (by means … containers, of boilers, on connecting feed pipe systems or near the appliances which they serve, to perform the same …