OFFICE DEPOT 9″ SECURITY DOUBLE-WINDOW 500 ENVELOPES -NEW. OFFICE DEPOT 9″ SECURITY DOUBLE-WINDOW ENVELOPES. 500 COUNT. WHITE WITH 2 WINDOWS. ENVELOPE MEASURES: 3 7/8″ x 8 7/8″. THE TOP WINDOW MEASUREMENT IS 1 1/8″ x 3 1/2″. BOTTOM WINDOW 1″ x 4″. Brand new.