Window trickle vents prevent the formation and retention of excessive humidity in rooms. These products are a vital part of room ventilation systems especially during heating periods. The trickle vents provide suitable air circulation, which prevents water vapour condensation on windows, and as a result stops to the growth of fungi. The Slimline series features an internal supply air control and an outer sill. They are installed on the upper part of windows by means of quick-mount sprung clips. Suitable for PVC windows.