Earphone Dust Filter 4.7mm This is a metal dust filter to be attached to the nozzle of earphones. It has a diameter of 4.7mm and adhesive only on the outer circumference of the back. It has little to no effect on sound quality. A set of two (1 pair). We are selling 3.7mm, 4.0mm, 4.2mm, 4.5mm, 4.7mm, and 5.0mm. We also accept multiple purchases.