No. 10 colored envelopes are perfect for your mail, classroom notes or any correspondence in need of a special pop of color. From the classroom to your craft room, these envelopes are the perfect way to brighten someone's day & make sure notes from home don't get lost in the shuffle of a backpack or regular mail. 24 lb. envelopes ensure easy printing with a distinctive look. Acid-free, lignin-free construction lets you display & store your creations with confidence without yellowing over time.