DiscKeeper Single - Inspired by the old-fashioned "rice paper" record sleeves, this antistatic CD sleeve is made from 100% virgin high density 3 mil polyethylene. HDPE provides many of the benefits of Tyvek, a spun form of the same material, at a fraction of the cost. The DiscKeeper is a tough cd envelope -- puncture resistant and moisture resistant. It is more rigid and retains its shape better than typical plastic cd sleeves.