The TK23 fuelling nozzle is designed specifically for the filling and discharging of cylinder bundles, e.g. on trailers. The Type TK23 is equipped with a PIN, which opens the check valve in the non-filter type TN5 receptacle and releases the flow. Now the cylinders can be filled or CNG can be discharged.

Connecting and disconnecting can only occur in depressurised condition. The TK23 is not equipped with an integrated check valve.