Double-window, No. 10 envelopes make mailing easy and efficient with Redi-Seal Closure. Envelopes do not require moisture to seal. Unique double-flap design keeps the gum from sticking before use. Simply raise the lower flap and press to seal. The 1" x 3-1/2" top window is positioned 1/2" from the left and 2-1/2" from the bottom. The 1-1/8" x 4" bottom window is positioned 1/2" from the left and 3/4" from the bottom. 24 lb. white wove envelopes also have poly windows and inside tint for security.