There is no difference, they are the same. A double-rub is the ability of fabric to resist surface wear caused by flat rubbing contact with another material. In the Wyzembeek abrasion test, fabrics are rubbed along the warp and weft of the fabric, with one back and forth motion equaling a double rub. The abrasion rating is determined by the number of double rubs made before two yarn breaks occur.
•    Light Use: 9,000 double rubs
•    Medium Use: 15,000 double rubs
•    Heavy use: 30,000 double rubs
•    Maximum use: more than 30,000 double rubs