Simplify mailing with durable, easy-to-use envelopes Ideal for bulky items that should be kept flat, such as brochures, pamphlets, magazines and more. Rectangular flap with gummed seal ensures secure closure. Made of 80-lb paper. LUX Envelopes, Open-End, 9in. x 12in., Baby Blue, Pack Of 1,000 is one of many Lined & Invitation Envelopes available through Office Depot. Made by LUX.