FAW T99 DT990 pro 80ohm Works on PC and Sony without problems and without an external sound card. The headphone is excellent, open back ear, meaning the back of the headphone is open, allowing you realistic sound and letting in external sound so you don't suffer problems if someone calls you and you're not completely isolated from your reality. The reason for selling is that I'm getting headphones that require a sound card. Price is negotiable.