Origin:Mainland China Din:One Din Certification:NONE Size: 4 inch:Outside diameter:98mm 2%; Inside diameter :64mm 2%; Convex outside diameter:90mm 2%;Convex inside diameter:72mm 2% 5 inch:Outside diameter:122mm 2%; Inside diameter :82mm 2%; Convex outside diameter:112mm 2%; Convex inside diameter:91mm 2% 6 inch:Outside diameter:155mm 2%; Inside diameter :103mm 2%; Convex outside diameter:141mm 2%; Convex inside diameter:115mm 2% 8inch:Outside diameter:195mm 2%; Inside diameter :136mm 2%; Convex outside diameter:180mm 2%; Convex inside diameter:146mm 2% 10 inch:Outside diameter:246mm 2%; Inside diameter :179mm 2%; Convex outside diameter:230mm 2%; Convex inside diameter:195mm 2% Methods of replacing: Remove the gasket and rub off old foam, apply contact cement(not included). Center the surround evenly as you place it on cone. Squeeze the inside of surround to cone with thumb on top and index finger up inside the frame,underneath the surround and go around a few times until it adheres. Apply elmers wood glue to outer frame, press down surround. Re-glue gasket to outer surround. Package included: 1 pcs