Acquired two models for our front bedrooms as we've been on a loud principal road. Installed them yesterday and the primary difference in noise is remarkable. I went for the 6.4mm laminated glass and positioned the units within the entrance in the window sill to provide optimum gap. Improved https://expert-london-tiler90134.estate-blog.com/33746151/a-secret-weapon-for-fire-rated-secondary-glazing