Top Quality Cat6a stranded shielded Copper Network Cable made by Excel. 60 cm length RJ12 to RJ12 made with Stranded Cat6a twisted pair cable. RJ12 plugs fit all RJ11 sockets. Uses a special and expensive extended Shielded RJ12 plugs these are much stronger/better crimp so stop any chance of cable pull out due to the cable being strained at angles!
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