Couple two sections of 6"x4" FiberRunner® Routing System channel (sold separately) together with the FRESPKT6 FiberRunner® Expansion Splice Kit - 6"x4". Couplers can be installed anywhere in system with the exception of where Lower Trough Support Brackets (part number FDFLMBKT6, sold separately) are located. This coupler kit contains one 6x4 FiberRunner® Lower Trough Inner Coupler, one 6x4 FiberRunner® Lower Trough Outer Coupler, two 1/4-20 hex nuts and one #8-32 screw.