White (500). Standard No. 9 (3 7/8 x 8 7/8) with Left Window Window Size is 1 1/8″ x 4 1/2″ positioned 7/8″ from left and 1/2″ from bottom Security Envelopes with Gum Flap Sturdy 24lb. White Paper with Blue Tint Proudly Made in the USA.