Further Information:
https://www.head-fi.org/members/rocksteady65.124498/
https://spares.sennheiser.com/catalog/product/003375-hd-450-ii
https://www.head-fi.org/showcase/sennheiser-hd-450-headphones.13526/
https://productz.com/en/sennheiser-hd-480/p/lgZB
https://tersaudio.com/sennheiser-hd480ii-review/
https://www.gramophone.co.uk/features/article/review-sennheiser-hd450-and-hd480-headphones
Any questions, feel free to ask.