Sirius Colour Filter No. 80A Medium Blue - Imaging Filters - Filters - Telescope Accessories - Sirius Optics
I went looking for examples and searched 80A filter and found very little on the main sub. So here is Velvia 100 with an 80A filter including a comparison at the end.
Antares Set of (4) 2in Color filters #11, #21, #80A, #ND25 - KW Telescope
High Quality Optical Glass 80A Filter Made in Japan 52mm Kood
Cokin 020 A020 Blue 80A Filter A Series Used Bin #cu020 | eBay
Hoya Series VII Color Conversion Filter 80A - Accessory – Kamerastore
Wratten 80A Filter, M55, multi-coated, metal mount - WITTNER FILM
Filter Set #1 - #12, 23A, 58, and 80A | Astronomics.com
Formatt Hitech 80A Color Conversion Filter (82mm) BF 82-CTC80A
Castell #80A Blue Planetary Filter 30% Transmission
Hoya 55mm 80A Filter
Astro Essentials 1.25" #80A Medium Blue Filter | First Light Optics