We can offer all kinds ceramic seals,which can be used in all the faucets,pumps,etc. Material: 95%--99% alumina Size: According to customers' request The frictional times are 300, 000 to 500, 000, the density is3. 6~3. 7g/cubic centimeter, the rigidity is 84~86 HRA, the thickness tolerance is less than 0. 02mm, the diameter tolerance is less than 0. 02mm, meanwhile, we can manufacture according to customs' drawings and samples...