Sennheiser HD598/HD558/HD518 have been regarded as one of the standard open-air headphones and obtained many enthusiasts using it for not only audio listening but also for watching movies due to its good sound frequency balance and a sense of release.
On the other hand, as a reference model for sound professionals and studio monitoring, Ultrasone Signature Pro and KRK KNS8400/KNS6400 has been released into market in 2011.

All of these models has cable detachable and been applied same type of structure for thier jacks. Due to this fact, there has been many requests from customers who are looking for and want to change the cables for better sound quality and usability to fit their various sound preference and using situations.

However, for the bayonet locking structure applied to these models, the plug has to be very accurately designed and be durable for repeated insert/eject activities. As a result of doing many cut-and-try, we have achieved to solve some problems and released as HPC-35HD598/HPC-62HD598 in Fall 2012.