A simple Male 3.5mm jack to Female 3.5mm jack extension cable, LINDY audio 3metres long. The connector strain reliefs are properly bonded to the sheath of the cable, and the cable feels nice and durable. Only time (years?) will tell how good it really is, but it has good promise.
Audio performance is good, with no cross-talk, and there are no crackles with handling, and no buzz is picked up even when wrapped around a compact fluorescent. I've used it for extending a microphone cable, for extending a lead between player and amplifier, and also for extending a headphone lead.
So, five stars.