OEM No. 10 envelopes designed for secure mailing with a blue ink inside tint for enhanced privacy. Each envelope features a window that displays the mailing address, with dimensions of 1-1/8" x 4-1/2" positioned 7/8" from the left and 1/2" from the bottom. Constructed from 24 lb. white wove paper, these security envelopes have a contemporary seam and a gummed flap for secure sealing.