A tiny seal with impressive dB reductions. This seal is only 5mm wide and once fitted only three thin 4.2mm long blades are visible, giving a discrete finish without compromising acoustic performance. The NOR720 also has smoke seal capabilities in accordance with BS 476 Part 31:1 and its design is based on ‘dual air pocket technology‘ which acts in the same way as triple glazing. We have cycle tested the NOR720 acoustic seal up to 100,000 opening and closing cycles.
 
The recommended gap tolerance is 3mm - 4mm.