Tyvek Evidence Envelopes are made of breathable material that is stronger than paper. Tyvek envelopes are rip-resistant, puncture-resistant, and water resistant, with a distinctive look and feel that make them stand out from all other envelopes or bags. Perfect to accommodate heavy or irregularly shaped items. Preprinted with all the pertinent information when collecting evidence at a crime scene. Features self-sealing adhesive flap to easily secure your evidence. Evidence tape or seals should be used to ensure evidence integrity. 9½” x 12½” white envelopes imprinted in black text. Custom printing available. Tyvek envelopes provided in packages of 50 or in bulk packages of 500.