Newpowergear 12" Foam Speaker Surrounds SubWoofer Edge Sub Woofer For SONY SS-U591AV SS-U621AV SS-U631AV SS-U701AV SA-W30, SAW30, SS-C600, SSC600 Two (2) 12 (304.8 mm) Premium Replacement Foam Surrounds. Inner Diameter : 8.5" (215.9mm). Inner Diameter after Roll :9.1" (231.14mm). Outer Diameter before Roll :10.5" (266.7mm). Replacement