Cord operated non-electrical fan, shuttered for toilets, boats, caravans and sheds etc. Performance: 5093mm2. For use with single pane glass. Aperture 121mm. All Vent-A-Matic models are designed for simple two part fitting into the glass aperture. For additional security and weather tightness, a little silicone glazing sealant can be applied to the external retaining ring. Vent-A-Matic ventilators can be cleaned with normal window cleaning materials.