SECURE SEAL: A unique and aggressive adhesive provides a strong, moisture-free secure seal ENHANCED SHELF LIFE: Six times longer shelf life than standard latex adhesive envelopes SECURITY TINTED: Be at ease knowing your contents will remain secure and private TAMPER-PROOF: Small perforations along the flaps provide better evidence of tampering FEATURES: 500 White, 4.125 x 9.5 Window Security Envelopes