The plastic clamp brackets allow for a quick installation of aluminum blinds with steel top rails measuring 25 x 25 mm in just seconds. Simply slide the clamp holder onto the window frame from above and click the blind into place – the aluminum blind is now securely hung. For blinds up to 90 cm wide, 2 clamp holders are sufficient. For wider aluminum blinds, at least 3 clamp holders should be used, adding one additional clamp holder for every 45 cm of width to ensure optimal stability. Pack of 3.