ROTK items are sorted into 5 groups. Each value shows the version that set it.
Healing
Healing items restore HP instantly, then over time, after an application time during which you are vulnerable. Since v1.3.0 they can be used straight from the ground (Proximity section). healing page →
Armor
Helmets and armor absorb damage, then break. Each type has its own visual and sound feedback when hit (v1.0.0). armor page →
Grenades and explosives
Five grenades have been supported in Solo since v1.3.36. Their damage and the flash effect take cover into account since v1.3.98. grenades and explosives page →
Shoes
The shoe tier changes running speed and reduces fall damage (v1.2.0). shoes page →
Backpacks and capacity (Bulk)
What you can carry is measured in "Bulk". Total capacity depends on the clothing and containers you have equipped. backpacks and capacity (bulk) page →