There are different joint locks:
- MDM0JLD dual joint lock for attaching two arm assembles (one monitor at each side)
- MDM0JLS single joint lock for attaching one arm assembly (one monitor). to the pole module (MDM0PL, MDM0PS)
Pls note these Joint Lock is NOT compatible with MDM11S, MDM12D, MDM12Q series multi LCD monitor arm desk mount bracket.