The ULINE Stay Flats 5 1/8 x 5 1/8″ White Self Seal Cardboard Mailer (S-2663) is a high-quality shipping product perfect for securely packaging and shipping small items. Made in the United States, these mailers are designed to provide a sturdy and reliable delivery solution for businesses and individuals. With no modifications needed, these self-seal mailers offer a convenient and efficient way to ship items in the mail.