These are BRAND NEW 12" (2.5 mil. thick!) premium plastic resealable outer sleeves (12-3/4" x 12-3/8" + 1-1/2" flap or 324mm x 315mm + 38mm flap). The thickest Biaxially Oriented Polypropylene (BOPP) on the market! These archival quality crystal clear sleeves are a great choice for protecting your precious record collection. The special adhesive used on this sleeve allows you to open & reseal the record many times, keeping your vinyl safe and dust-free. Biaxially Oriented Polypropylene (BOPP) means a much better sleeve clarity than the traditional cast polypropylene or polyethylene. The resealable adhesive strip is located on the body of the bag, allowing for easy record insertion & removal. 25% Thicker than 2mil sleeves!