Two RCA phono plugs to two RCA phono plugs with twin audio cable. These cables are often used to connect between TVs, DVDs, VCRs, PCs and games consoles, but they have lots of other uses.
Breadboarding sound-studio stuff, I've been bitten by croc-lead resistance. Anything from an ohm to 3 or 4. That's enough to shift a DC working point, or create unsuspected ground-coupling. Therefore delighted to find these from Rapid: very low wire resistance, good grip.
Design is not quite perfect: like most of the others, from different suppliers, the sleeves slither a bit, slowing you down. Dab of superglue will fix it, but you probably have better things to do!