White open end envelopes are perfect for sending documents and cards that cannot be creased or bent. Measuring 6 X 9 inches, these envelopes can easily fit inserts, measuring 5.75 x 8.5 inches. That’s an unfolded piece of A5 sheet or any standard-sized greeting card or invitation card. The 6 X 9 white open end envelopes are also known as catalog envelopes. Mainly because it’s the envelope of choice for sending product catalogs to customers and clients. Apart from catalogs, these envelopes can be used to send jumbo cards, documents, and letters. Customers can choose to get their company logos and contact information pre-printed when ordering these envelopes.