THIS IS FOR (QTY 2) MDF 8 INCH SPEAKER RING INSIDE DIAMETER --- 7 1/8 INCHES OUTSIDE DIAMETER ---- 8 1/2 INCHES THICKNESS -- 3/4 ALL RINGS ARE MACHINED FOR PERFECT ACCURACY PLEASE CONTACT US FOR CUSTOM CUT RINGS & SIZES WE HAVE MULTIPLE MDF RING SIZES & STYLES THESE ARE GREAT FOR BUILDING FIBERGLASS BOXES, CUSTOM SPACERS