【 Reduce Light Leakage 】: Our light gap blockers effectively stop the light from coming in through the sides of your blackout blinds & shades Creates a dark environment for you and helps protect your privacy and quality sleep 【 Metal Light Blockers 】: U shaped light blocking channel is made of thickened aluminum alloy, high strength without deformation. Built-in soundproofing strips reduce wear and tear on curtain edges and corners 【 Cuttable Light Block Strips 】: 1.27x3.81cm (1 /2x1 1/2") U-shaped window light panels. Light blockers for blinds can be easily trimmed with a hacksaw, to fit different blackout shades sizes for Blackout 【 Drilled Installation 】: Window side light blocker needs to be put right location. Make sure that the curtains can be pulled up and down, then drill holes and secure them with screws. The gap blockers can be used repeatedly after removing the screws 【 Multiple Scenarios 】: The blackout blinds side tracks perfect for those who sleep during the day, those babies who woken up by the sun, apartment and home theater. Works on roller shades, blinds, zebra shades, roman shades (Cellular shades, honeycomb blinds not applicable）