Gladen German Technology | ref: Gladen Zeta ZM 70 noir

https://soundautoconcept.com/collections/haut-parleurs-medium/products/medium-haute-fidelite-gladen-zeta-zm-70-noir#:~:text=Medium%20haute%20fid%C3%A9lit%C3%A9%20%C2%A0%20Gladen,20ZT%252070%2520v2.pdf