10 inch - (250mm x 40mm) - Borosilicate (Pyrex)-  F6  - parabolic - telescope  mirror.

Aluminum (Al/SiO) coating tested and inspected.

SPECIAL PRICE! - ONLY 1 LEFT! - IF YOU WANT TO BUILD A VERY BIG TELESCOPE YOU WILL NOT FIND A MIRROR
OF THIS QUALITY FOR THIS PRICE!