SENNHEISER H-82370-1/4" Stereo Phone Screw On Adapter for Sennheiser HD280PRO gold-plated construction provides excellent signal transfer and resists corrosion The adapter can screw onto threaded 1/8" (3.5mm) plugs Stereo Phone Screw On Adapter for Sennheiser HD280P Headphones Also Compatible with Sennheiser HD 212, HD 477, HD 497, EG 350 Headphones Also Compatible with Sony MDR-7506 and MDR-V700 And Philips HP910