I'm a Voice Actor working out of L.A. As just about anyone living in the city can tell you, things can get REALLY loud around these parts. To make matters worse, landlords have little incentive to install windows capable of reducing outside news, as the weather is generally mild and, well, when it comes to the noise, you moved to the city. What did you expect...? While the inserts are not an alternative to an isolation booth, as low end frequencies that plague voice actors can still penetrate (Albeit significantly muffled) the inserts, the overall ambient noise from the world outside is DRASTICALLY reduced when having the inserts properly installed; and can certainly benefit anyone who who's limited on space, isn't looking to shell out several thousands of dollars for a booth, or in my case, has a single wall booth that's still susceptible to intrusion form higher outside frequencies. Needless to say, my number of 'did the mic hear that?' moments have certainly been reduced! (To be clear, these are not an alternative to a booth or place of isolation, rather, they can help with the overall levels of intrusion from outside noise) As an added bonus, unrelated to Voice Acting, living near the ocean can bring lots of moisture to the inside of the windows on cooler nights. I often find myself having to open the windows when it's cold out, or use a squeegee to wipe away the condensation. The inserts have not only eliminated the moisture, but they've also helped maintain a more consistent temperature throughout my unit, thanks to a reduction in outside airflow into the unit. Overall, I'm definitely happy with my purchase!