how can you tell who can use what items and what slots they will fit in? Thanks
1st indicator: Color. For example Mental Tool is violet and the mental tool mods are always violet too. Sadly there are lots of different items with similar colors still ...
2nd indicator: READ. You have to read the description. The item type of a mod is always in the headline. For example it will say " xyz for Precision Ranged Weapons". Which means the mod is for Precision ranged only. If it says "xyz for Ranged Weapon" the mod is for ANY ranged.