Fotoimpex Pergamine Paper Negative Sleeves For 120 Film are cheaper than “plastic” sleeves and somewhat more archival because of the porousness allowing any moisture to evaporate.
Because Pergamine Paper is translucent, so you’ll have to take the negatives out to closely look at them or make contacts.
The sleeves fit in 2, 3 and 4 ring binders. The Pergamine Paper is absolutely chemically neutral and archive-safe.
Each Sleeve Fits: 6×6, 6×7 and 6×9 negatives in 4 rows