These worked better then I could have imagined. I live on the first floor on a busy avenue in NYC. my bedroom windows are right off the street. When I moved in I could hear entire conversations of people walking by, Street/car noise, Trash pickup, construction, essentially anything that made a some noise within 100 feet of my windows. I’m an audio engineer and from years of training have developed very acute and sensitive ears. I tried so many ways to DIY fix the sound issue. None were sufficient. I pulled the trigger on these window inserts and splurged for the acoustic treated versions and it was INSANE!!! without getting too technical regarding my SPL measurements before and after , there was approximately a 65-75% decrease in the level of noise. I couldn’t be happier. I don’t have to close my curtains to help with the noise and I sleep like a baby again. Even my little puppy who definitley has better hearing then I do is never disturbed. On top of all that they look great you don’t even notice them there. In fact I had a friend smack his face on it thinking he could look out the window not knowing there was an inner panel.