Without precision engineering in this critical area, wind pressure can push moisture-laden air through the corner and up the frame, leaking into the home and rotting the frame.

• Fit securely behind the weatherstrip to help block wind-driven moisture infiltration.
• Designed to mate with our inswing sills to complement weathersealing performance. (Not required for outswing sills.)
• Flexible, foam-filled material holds its shape over time, protected by a durable jacket to resist moisture and wear.