The Sennheiser HD 400 Pro are a pair of professional mastering headphones. They are the first pair of open-back headphones in the company's Pro lineup, which has only had closed-back headphones until now. The HD 400 Pro are essentially Sennheiser's HD 560S with slight modifications, none of which are to the sound. Compared to the 560S, the HD 400 Pro come with a slightly altered design and an extra cable in the box and for that, they cost a bit more. Design The design of the HD 400 Pro is nearly identical to that of the HD 560S, which itself looks similar to several other HD...
Source: https://www.gsmarena.com/sennheiser_hd_400_pro_professional_wired_headphones_review-news-55637.php
