These protective sleeves are typically made from OPP (Oriented Polypropylene) material, featuring the following characteristics: High Transparency: Clearly displays the stamp's design, colors, and details, facilitating appreciation and authentication. Abrasion Resistance: Offers a degree of wear resistance, reducing friction damage to stamps during routine storage and handling. When using OPP stamp protection bags, observe these precautions: Select appropriate size: Ensure the bag size matches the stamp to prevent shifting or compression due to oversized or undersized bags. Handle with care: Move stamp-containing bags gently to avoid damaging stamps through excessive force. Avoid direct sunlight and high-temperature environments.