Specifications:
1.Length:Approx. 50CM/19.68inch;allowed 0.1-2mm error
2.Main material:Foam
3.Outer diameter:33mm;allowed 0.1-1mm error
4.Inner diameter:21mm;allowed 0.1-1mm error
5.Thickness:6mm;allowed 0.1-1mm error
6.Package Content: 1 pair or 2 pieces