A fluid coupling system is provided including a fluid coupling having a cooperative key coding system and latching mechanism, a valve biasing mechanism with corrosion resistance, and other advantageous features. The key coding system permits interconnection of only matched coupling members while preventing the inadvertent interconnection of mismatched coupling members notwithstanding the presence of many coupling, both matched and mismatched. The coupling includes first and second coupling members that are releasably slideably, axially interfitted with their passageways in fluid communication. The key coding system includes key coding elements on the coupling members that are axially movable into matched interengagement when the coupling members are matched but are precluded from moving into matched interengagement when they are mismatched, all without rotation of the couplings or the key coding elements irrespective of the relative rotational positions of the couplings members or coding elements. The latching mechanism is movable axially and radially of the coupling members between latching and unlatching positions, again without relative rotation of the latching mechanism and coupling members. The key coding system allows the latching mechanism to move into latching position when the key coding elements match but precludes such movement when there is a mismatch. Although the key coding system and the latching mechanism do not require rotation to function, they allow relative rotation of the coupling members. Furthermore, the coupling incorporates a valve biasing mechanism that does not use a metallic spring or other corrodible parts in contact with the corrosive chemicals.