-- backpack research -- researching mining efficiency increases your backpack capacity (inventory slots) local Event = require 'utils.event' local function on_research_finished(event) local force = event.research.force local toolbelt_bonus = (force.technologies['toolbelt'].researched and 10) or 0 local prod_bonus = force.mining_drill_productivity_bonus * 100 force.character_inventory_slots_bonus = prod_bonus + toolbelt_bonus end Event.add(defines.events.on_research_finished, on_research_finished)