No. 10 business envelopes feature double windows and a security tint to secure your documents. Top window is 1" x 3", 1/2" from the left side and 2-1/2" from the bottom. Bottom window is 1-1/8" x 4", 1/2" from the left, and 3/4" from the bottom. Design also features a white wove material, side seam and gummed seal. 24 lb.