The Columbian #10 Security Envelopes are a rectangular shape with a self-seal closure, making them convenient for sealing and shipping documents. With a size of 4-1/8 x One Size and a color of white, these paper envelopes are perfect for secure and professional communication. The box contains 500 envelopes, weighing 6.34 pounds, manufactured by TOPS Products under the brand Columbian. Ideal for businesses and industrial use, these envelopes provide a reliable option for mailing and packaging needs.