Hi, I have a set of KEF 1005's and they use metal springs that you push in and place the cable in before letting the pin spring back thus trapping the bare speaker wire.
From a photo they can look like like little black/ red sockets but they are in fact like a little button (spring) that you push inwards so that you can insert the speaker cable. Cannot be used with banana plugs but guess the benefit is a direct connection and cost saving.
Nice smooth sound too
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