^its an extract, 15x means the potency of it is 15 times as great as regular untreated substance. so 1 lung full of 15x dagga would equal 15 lung fulls of regular dagga. so basically its good cause you need to only use a minimum amount of a substance to achieve its full effects. extracts come in different amounts (5x, 10x, ect.), and different substances have extracts not just dagga, salvia comes to mind as well as other stuff.