This 17x21 rigid mailer (50 Pack) is the ultimate solution for safely packing and shipping your books, clothes, calendars, disks, documents, postcards, letters, DVDs, magazines, and pictures, and for packaging art prints to send to your friends and family. These padded cardstock mailer envelopes are designed to resist bending and stay flat to help ensure that your items arrive at their destination in pristine condition. This 550gsm thick cardboard mailers protect against the common tears and bending that can occur with more common, less thick envelope mailers, giving you peace of mind that your items will arrive safely. These 17x21 cardboard envelopes feature a professional clean, white design, making them ideal for business and personal use. Whether you're sending important business documents or cherished family photos, these mailers will help to ensure that your items arrive in the condition you intended. With a bulk pack of 50, you'll have plenty of stay flat mailers on hand for all your shipping needs. They are lightweight and easy to store, making them a convenient mailing solution for business and home use alike.