Top-mounted roller shutter system is a product addressed to those who look for functional solutions. SKT OPOTERM-based roller shutters are intended for both newly constructed and refurbished buildings (replacement of windows). This on-window mounted system has its box direct installed on the window frame by means of an appropriate profile. These profiles are compatible with the majority of window and door frame profiles (aluminium, wooden & PVC). Boxes are made of high quality PVC components and are characterised by an increased thermal insulation. Opoterm top-mounted roller shutter system has received a thermal transmittance-related certificate from renowned research centre IFT Rosenheim. The roller-boxes were tested using EPS (Neopor, thermal insulation material) – the tests were based on the current standards and calculation methods. The product demonstrated a very good thermal transmittance performance, e.g. the SKT 230/170 box with integrated insect screen obtained a Usb coefficient of 0.73 W / (m²K) while maintaining high operability to shadow larger glazed areas.