Sennheiser KBL - HD 518, HD 558, HD 598 (archived) - - Connection cable
Geekria Shield Headphones Case Compatible with Sennheiser HD 599, HD 598, HD 560S, HD 559, HD 558, HD 555, HD 400 Pro Case, Replacement Hard Shell Travel Carrying Bag with Cable Storage (PU Brown) - Walmart.com
OFC Replacement Braided Cable Cord For Sennheiser HD 518 558 569 579 599 598 CS Se HD518 HD558 HD569 HD579 HD599 Headphones - AliExpress
Amazon.com: GEEKRIA Boom Mic Headphones Cable Compatible with Sennheiser HD 599SE 598 560S, 2.5mm Jack Nylon Braided Replacement Cord with Boom Microphone and Volume/Mute Control for Gaming & Meeting (6 ft) :