OEM Quality Park No. 8-5/8 check window envelopes, featuring a blue ink inside tint for increased privacy and a window to display the mailing address. The 1" x 4-1/16" window is positioned 1" from the left and 3/4" from the bottom. These 24 lb. security envelopes are constructed from white wove material, with a contemporary seam and gummed flap for secure sealing.