A: Great questions! A gross is a unit of measure, which means 144 of any item. A 10-Gross bag of rhinestones will contain 1440 rhinestones. The SS10 or SS20 refers to "Stone Size". The smaller the ss the smaller the rhinestone. SS10 is the most commonly used size for designs and Crystal is the most versatile color we use. SS20 stones are both larger diameter as well as taller rhinestones, which means they must be pressed at a higher temperature for a longer dwell time than ss10 rhinestones.