Bought 2 units for our entrance bedrooms as we are on a loud main highway. Mounted them yesterday and the primary difference in noise is wonderful. I went to the 6.4mm laminated glass and positioned the units about the entrance with the window sill to offer greatest gap. Image: https://walesw345mmj5.life3dblog.com/33543859/soundproof-windows-things-to-know-before-you-buy