3.5mm Headphone Adapter Headphone Adapter Aux Cable Jack Plug Converter for Sennheiser HD 518 558 595 598SE Audio Technica| | - AliExpress
Amazon.com: LTGEM Headphone Case for Sennheiser HD 4.50/201/229/419/518/555/558/579/598/599 & Beats Studio3/Solo3/Solo2/Solo Pro Headphones : Electronics
Sennheiser HD 518 over-ear headphones $65 shipped (Reg. $130)