Purchased 2 models for our front bedrooms as we've been on a noisy major road. Installed them yesterday and the real difference in noise is awesome. I went for that 6.4mm laminated glass and positioned the units over the front of the window sill to present optimum hole. Image: https://gustaveo974lmk2.daneblogger.com/33682737/not-known-details-about-soundproof-windows