How about these?
www.amazon.co.uk/Greyboard-3000mic-Backing-Mountboard-Crafts/dp/B08Y82Q8SH
( , Thu 11 Apr 2024, 18:25, archived)
www.amazon.co.uk/Greyboard-3000mic-Backing-Mountboard-Crafts/dp/B08Y82Q8SH
( , Thu 11 Apr 2024, 18:25, archived)