How do I use this speaker cable???

I feel a bit ridiculous asking this question, but I picked up a used pair of Linn AV5140 speakers this past weekend. They came with a pair of Audioquest CV-4 Cables that have been terminated for tri-wiring, however I'm unsure as to what type of connectors the cables terminate to on the Amp side. Can anyone identify these and explain how they are used?

See photo here (connectors on the right hand side of photo) - http://imgur.com/xTaL7oA

Their diameter is larger than that of a banana plug, and a banana plug can actually plug inside them...