BOWER sells FR4. Related information about FR4 includes: Model FR4 Inner diameter: 6.35 mm Outer diameter: 15.875 mm Thickness: 4.98 mm Series: Deep groove ball bearing. If you want to know more about FR4 related information, you can consult online or call the hotline , we will serve you in detail. FR4 has a wide range of uses. FR4 is mainly used in engineering machinery, machine tools, automobiles, metallurgy, mining, petroleum, machinery, electric power, railways and other industries. The price of FR4 sold by our company is reasonable and we look forward to cooperating with you.