It's a number 5 ykk on the BCS, separating. On other shelters they are a #8.

Lightweight Tipi Tents and Hunting Tents https://seekoutside.com/tipis-and-hot-tents/
Backpacks for backpack hunting https://seekoutside.com/hunting-backpacks/
Hot Tent Systemshttps://seekoutside.com/hot-tent-combos/