Business Source Double-Window Invoice Envelopes White is Perfect for sending checks invoices statements and moreNo. 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. Security tint keeps information hidden from view for added privacy. Transparent windows allow convenient use with printed labels. Gummed flap creates secure seal to prevent peeling during delivery. Seam: Side Seam. Material: Wove. Sold as 500/Box.