Staples Professional Kraft Bubble Mailer Envelope #3 - 8-1/2" L x 14-1/2" W - Pull-Tab Strip - 100 PackWith these #3 Staples Kraft Bubble Mailer Envelopes, you can mail fragile items with confidence. The mailer envelopes are designed with a square flap with side seams and an easy peel and seal closure so that contents can be securely and safely contained without the user needing to lick adhesive or use separate glues or stickers. A 0. 5 mil inner bubble layer cushions fragile items to help keep them safe during the mailing process.