Server

On Remove Item:

AddEventHandler('ak47_inventory:onRemoveItem', function(source, item, amount, slot, has)
    print(source, item, amount, slot, has)
    -- source
    -- item name
    -- number of item removed
    -- slot number
    -- how many item player has
end)

On Add Item:

AddEventHandler('ak47_inventory:onAddItem', function(source, item, amount, slot, has)
    print(source, item, amount, slot, has)
    -- source
    -- item name
    -- number of item added
    -- slot number
    -- how many item player has
end)