The noise reductiion after installing the Indow Accoustic Inserts is remarkable. Whereas before we would be woken up by the start of commuter traffic at 6 AM, we now sleep soundly intil WE are ready to wake up. The ordering, measuring and installation instructions are very detailed, but if you follow them closely you will have a great finished product. The corners are a little tricky to get just right and it takes a little finagling to achieve the right look. They were packed and protected well enough that even FedEx didn't damage them. I would absolutely use them again.