Inventory space is a survival resource. Stackable consumables, tools, and wearable equipment compete for capacity.
Equipment
Equipment applies its listed bonuses and trade-offs only while used in the correct slot. The Small Backpack adds 10% inventory capacity. The Flashlight and Lockpick Set occupy Equipment 1 and Equipment 2 respectively, and provide small loot-quality bonuses while equipped. The Gas Mask occupies the Head slot and trades movement speed for protection and visibility range.
Weight, stack caps, slots, and rarity-affix eligibility are part of the item definition. Do not treat a cosmetic presentation or an inventory label as proof that an item can be equipped in another slot.