【Why we need to install light blockers for shades】Most blinds and shades are smaller in width than the window to avoid the fabric rubbing against the wall when the blackout shade is raised or lowered. If your blinds or shades are always leaking some annoying light, then we suggest you install JOYENG light blocking strips. 【Double effect blackout】 JOYENG light mask is pasted inside the light blocking layer, and gives the gap blackout tape to avoid the gap leakage, and uses 2 kinds of blackout methods, it can really achieve 100% blackout effect! 【Easy assembly】 ① Measure the height of the window frame; ② Cut the blackout strip to the appropriate size; ③ Tear the tape and paste it on the window frame (if the wall cannot be stuck, reinforce it with screws)④ Paste the gap tape; 【Light-blocking Side Tracks】The blackout side tracks perfect for those who work at night and sleep during the day. Or, it can provide you with a dark environment when you want to watch a movie at home during the day one day. Works on cellular shades, honeycomb blinds, roller shades and blinds, roman shades and more. Recommended for inside mount blinds. If for any reason you decide that The Light Blockers are not suitable for your windows, simple return them within 30 days and receive a refund. 【After-sales Service】We provide high-quality product and service for every customer, If accessories or products are missing or broken, please message us and we will resend the accessories or products. If you are not sure if your window type is suitable, please check with customer service before ordering.