You asked, PMD delivered. Yellow is the brand's most intense disc, made for its die-hard users. It's ideal for buffing and smoothing out the roughest spots of the body. Each disc is embedded with aluminum oxide, which is a naturally occurring element that is second only to diamond in terms of its hardness. The aluminum oxide provides the most effective results and completely eliminates the possibility of spreading bacteria that may cause breakouts or irritation, which is a risk when diamond tips are used.