Each of these envelopes is made out of earth friendly 30% recycled, smooth, high quality, 24lb paper. The colors included in this assortment are blue, red, orange, green, purple, and yellow. Each of these envelopes has a straight flap and a reliable gum closure. The size of these envelopes makes them deal for three-times-folded standard sized sheets of paper. Use them to send personal letters, business letters, newsletters, documents, forms, and more. Details:Includes an assortment of colors4.125" x 9.5" (#10) 24 lb.150 envelopesFeatures a rectangular straight flap closurePaper