These connectors use an LC to LC coupler to extend a single-mode fiber connection by connecting two LC duplex cables, use an MPO/MTP coupler to extend a multi-fiber connection by joining one keyed male MPO/MTP cable end to one un-keyed female MPO/MTP cable end, or use an MPO/MTO coupler to extend a multi-mode fiber connection by connecting two OM3/OM4 MPO/MTP trunk cables.