These Quality Park™ catalog mailing envelopes feature a quick-and-easy Redi-Seal™ closure ideal for bulk mail. Redi-Seal™ envelopes have pressure-activated latex adhesive on two surfaces. Just press together for a strong, durable seal. No paper strips. No moisture required. Redi-Seal™ envelopes are the perfect mailroom update for concerns about surface germs in the workplace. Skip the yuck, save time, and cut waste with every mailing. These self seal envelopes are inkjet printer compatible, though not recommended for the laser printer. Made of 28 lb stock that can withstand extensive handling through the mail. Center seams give added strength for heavy contents. USPS Air Mail®. Seam Type: Center; Flap Type: Cheese Blade; Trade Size: #13 1/2; Security Tinted: No.