The FCK008 is a union connector for FUSION fixed or tilt wall mounts which adds 8" (203mm) of length to the poles.
Helps create single row multi-monitor applications such as menuboards
Typically use FCK008 with 37-42" screens and the LSAU, LSMU, LTAU and LTMU. The FCK000 is used with the MTAPU and LTAPU portrait mounts. All other screen and mount combinations typically use the FCK016.