Loot bag
The loot bag increases the number of loot items you can carry. IGN lists tier 1 as 60 items with sambar skins and tier 2 as 90 with pig skins; later tiers are also mentioned.
How it works
The first two tiers provide specific carrying limits, while the excerpt only says that tier 3 uses demon fish skins and carries more loot items. IGN suggests considering an oversized loot bag before attempting to craft every gear upgrade, because materials and other items take inventory space.
Your next step
Consider increasing loot capacity before gathering materials for many upgrades.
Read the supporting references
Base-game equipment crafting progression and the supported distinction between the Tiger and Elephant skill trees. No edition-specific differences are established by the evidence. Guidance explains the referenced mechanics; it is not a tested damage ranking. Check the stated edition and source version before applying a patch-specific detail.