No 10 Window Envelopes Self Seal - Left Side Window Envelopes for Invoices and Letters -Blank Security Tinted (Pure White Color) - Pack of 500 BLANK FORMAL DESIGN: These No 10 security envelopes have a pure white color and a blank design. These left window envelopes have a classic design with rectangular flaps and dual parallel seams. SECURITY TINTED: Perfect window envelopes for checks and sensitive documents, these envelopes are security tinted. The quality security tint makes it impossible to read the contents of the envelopes without breaking the seal. SELF SEAL: The envelopes are supremely easy to seal as the come with an easy self-seal mechanism. This saves both time and effort, especially when sending mass marketing mails. ENVIRONMENTALLY FRIENDLY: The self seal technology doesnt require you to peel off a plastic strip. This greatly reduces plastic waste. IDEAL FOR REGULAR USE: These envelopes are made from 24 lb white stock paper, which grants them enough durability for regular office usage. This pack of 500 left window envelopes offers you great value. Perfect for stocking up for offices, the packs are easy to store and stackable.