Material:PP for back up pad,and the middle layer is EVA. Use:for DIY market Size:3",4",4.5",5", ... 6",7" This DIY pad is common quality pad,it is ... DIY market,most of DIY market in the world use this grade of pad.because it is cheap.Material:PP for back ... up pad,and the middle layer is EVA.Use:for DIY marketSize:3",4",4.5",5",6",7" DIY polishing pad