These Quality Park catalog mailing envelopes have a quick-and-easy Redi-Strip closure. Just peel the paper strip & press for a strong, durable seal. Redi-Strip envelopes are the perfect mailroom update for concerns about surface germs in the workplace. Skip the yuck, stay safe & save time with every mailing. Plus, the peelable paper strips protect your adhesive from dust so envelopes last longer in storage. These self seal envelopes are inkjet printer compatible, though not recommended for the laser printer. Heavyweight 28 lb Kraft paper is opaque to protect private contents & durable enough for lots of hard office tasks. Center seams give added strength for heavy contents. Seam Type: Center; Flap Type: Cheese Blade; Trade Size: #13 1/2; Security Tinted: No.