No. 10 business window envelopes feature a removable sealing strip for a clean, quick seal without moisture. Simply peel back the strip and fold the flap closed. Pressure-sensitive gum forms a permanent bond. The paper strip keeps the adhesive free of dust, ensuring a long shelf life. White wove envelopes are security tinted. 24 lb. envelopes come in a bulk shipping container to reuse as letter-size file box for home or business use.