Formatt Hitech 80A Color Conversion Filter (82mm) BF 82-CTC80A
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.
Filter Set #1 - #12, 23A, 58, and 80A | Astronomics.com
Cokin P Series P020 Blue 80A Filter – Cambrian Photography