The M-D V-Flex Window Seal is designed to protect against drafts, moisture, dust and insects. Save on energy by sealing windows keeping the heat or air conditioning from escaping. Made of flexible plastic this seal is designed for double-hung windows and self adjusts to form a weathertight seal. Easy to install - just peel and stick. Apply to a clean and dry surface. No hardware required. Before installation, cut to desired length using scissors.