An enhancement function.
Players select a battle girl and equipment that can be enhanced. The equipment is indicated with a star(s) to the right of the equipment icon. If the equipment has an empty star(s), players can select it and choose sacrificial material that appears in a pop-up menu after selection. The sacrificial material offers varying amounts of enhancement points depending on rarity and whether the material is a component of a greater material. Once the enhancement meter is filled and the enhancement is a success then the empty star(s) turns blue. Once all stars turn blue no more enhancement can take place.
Please note that these Lab enhancements with their additional stats do NOT carry over upon promoting the battle girl. Therefore, it is advised to exercise common sense when and when not to enhance them, or if at all.