Designed to fit standard letter size paper, with a wide opening for easy envelope stuffing. Our envelopes can fit up to 60 sheets of paper and have a 3” x 3.75” window on the left side to show address or other business information to the recipient. Gummed flap closes securely when moisture is applied and is a cost-effective option for bulk mailing. Sturdy 28lb white wove paper and OUTSIDE seam make these the perfect envelope for automatic insertion using a machine. Bulk pack of 500 envelopes extends the time between ordering and provides great value.