Store important documents in these acid free envelopes. Colorful, durable poly material is tear and water resistant and easy to clean, making these envelopes great for keeping everyday papers organized too. Tough and acid free, these clear envelopes are ideal for the home or office. Expands 1.25". String-tie closure to secure contents. Closed on three sides for security and portability. Open-Side—Horizontal orientation. Seam Type: Weld; Flap Type: Cheese Blade; Security Tinted: No; Opening: Open Side.