These are brand new 10" (3 mil. thick!) heavy duty plastic inner sleeves! They measure 10.125" x 10" (257.18mm x 254mm). High density stabilized polyethylene plastic provides the best possible protection against dust and scratches. These are our finest inner sleeves for records. They do not sweat like low density inner sleeves and stand up inside the jacket. These are the heaviest and best we've seen!! These cover the vinyl & slide into the record jacket.