Sony MDRDS1000 Digital Surround Sound Headphone System (Discontinued by Manufacturer) 40Mm Driver Units Closed-Type Design Compatible With Dolby Digital, Dolby Prologic Ii, Dts & Mpeg-2 Aac Analog & Optical Input Option To Connect Second Headphone Virtual phones technology creates exciting home entertainment with crisp, clear dialogue and dramatic sound effects High quality with a stylish design 40mm driver, close-type design Dolby Digital, Dolby Pro Logic II and DTS decoder 3 sound efect modes: Off, Cinema & Music