Attaches any 4x4 FiberRunner® Fitting or Channel to the 2x2 Fiber-Duct™ Channel, S2X2BL6 or E2X2BL6 or 2x2 FiberRunner® Channel, HS2X2BL6 or H2X2BL6. Note: Attachment to 2x2 FiberRunner® Channel requires a QuikLock™ Coupler FBC2X2BL. Includes solid cover.