500 Double Window Envelopes Self Seal Closure - Security Tinted Envelopes for Computer Checks - Bright White Payroll Envelopes (3 5/8" x 8 11/16") EASY-TO-SEAL: These double window envelopes come with a self seal feature. This means you dont need moisture to close the flaps. All you really need to do is peel off the adhesive strip, close the flap, and apply pressure. The ease of sealing makes these envelopes perfect for mass mailing. DUAL WINDOW DESIGN: The dual transparent poly windows are located at perfect positions to make sure the recipients postal details are visible from outside. The dual window design saves mailing effort and time. DESIGNED FOR CHECKS: These windowed envelopes for checks are perfectly sized (3 5/8" x 8 11/16) to fit a standard unfolded bank check. Often referred to as payroll envelopes, this is the most popular envelope type for sending checks via mail. RELIABLE SECURITY TINT: These self seal double window envelopes also come with security tint. This prevents anyone from viewing the printed banking information on the checks from outside.