Butyl tapes help prevent and reduce costly water damage. Tough rubber, pressure sensitive mass, offers excellent adhesion to a variety of surfaces (no applicators required). Used to to seal out: dirt, dust, moisture and water. Easy to use in tape form. Low moisture vapor transmission value. A must requirement in any sealing application. Butyl caulking is packed in a rugged, reusable, resealable storage package. Butyl caulking tape will remain sticky and continue to conform over many years and will not dry up or dry up and crack like many other sealants.