When there is a need to send sensitive information like say your QuickBooks checks via mail, you need security. Security tint envelopes are products that can help provide such a purpose. They are used to carry computer checks or manual business checks more often by the businesses. There is also a wide variety of usage of these envelopes for carrying other financial documents, or even personal and government correspondence. You can use these envelopes to send anything that you want to protect from prying eyes.