2020 3-Up Horizontal Laser W-2 Double-Window Envelope. Ensure immediate attention! Double-window envelopes come preprinted with the statement Important Tax Return Document Enclosed . Compatibility: Use with TF5210 and TF5211. Quality: 24# white wove confidential double-window envelope. Secure: Printed lining to protect your privacy.- 2020 3-Up Horizontal Laser W-2 Double-Window Envelope.