STC thirty–35 = That is an elevated level of sound abatement overall performance. You would possibly listen to a loud, out of doors discussion but wouldn’t be capable to make out the text. The frame is made from aluminum and gives overall flexibility to match unique architectural kinds and Choices. https://london-professional-tilin51616.bloggazza.com/26025218/the-ultimate-guide-to-condensation-resistant-glazing-in-wc1a