Koss KPH7

The headphone institutions buy by the box: Koss's lightest, cheapest wired on-ear. A slim adjustable band, soft on-ear pads, a 3.5 mm plug — and that is the complete feature list, which is the point. It fits nearly any head, shrugs off careless handling, and costs little enough that a lost pair is a shrug, not a loss.

Sound is serviceable: clear for speech, lessons, videos and background music, without the bass or polish of the dearer Koss on-ears.

Buy more than one. Desk, drawer, guest basket — the KPH7 is infrastructure, not equipment.