The invention is a needle valve and connectors for use in liquid transfer apparatuses. The needle valve of the invention is not the conventional type of needle valve known in the art that comprises a threaded valve stem, which allows very accurate control of the flow through the valve, and that uses elastic materials, such as rubber, as a sealing component. The needle valve of the invention comprises two components: the first component is a hollow needle having a smooth exterior surface and a port at the side of the cylindrical shaft, the second component is a seat made of rigid material e.g. plastic with low friction properties.