This is due to the better filters that are fitted to these newer units Supplied with 2 x M3.5 Faceplate screws. Simply insert Unstripped conductors and Close the Clip to connect. BUILT IN MICROFILTER - Integrated VDSL+ADSL Bell Wire Filter in the MK4 Front plate negates the need for microfilters at the Master or on your Extension Sockets.
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