Features a Tamper Indicating Panel (TIP) incorporated into the flap-the word "OPENED" appears in red to signal tampering. Durable Tyvek® envelope resists punctures, tears and moisture. Lightweight envelope saves on postage. Flap-Stik® self-sealing closure is simple to use. Envelope Size: 9 x 12; Envelope/Mailer Type: Security/Confidential; Closure: Self-Seal Flap-Stik®; Trade Size: N\A.