Might pay to read the ad more closely - follow your link and click on the "Larger picture" button and you'll see that the pack label states 6 tapes:4x3hours and 2x4hours - when I was at school 12 + 8 = 20.
Best Black Friday Deals 2017
Black Friday Deals for Designers & Artists: Adobe, Apple, Corel Painter, Microsoft Surface, Wacom &e…
Best Black Friday Apple Deals 2017
Black Friday 2017 : date, sites participants & bonnes affaires