Bulky weight yarn, this is a fat yarn! It has 7 wraps per inch (wpi) and a knit gauge around 16 stitches over 4 inches [10cm] +/- 4 stitches per inch).
Super Bulky weight yarn is even fatter yarn. This category is a catchall for all kinds of extremely thick yarns and rovings. It has 5-6 wraps per inch (wpi) and a knit gauge of 7-12 stitches over 4 inches [10cm] (3 stitches per inch or less).