Enhance your ventilation system with the 100mm Underfloor Vent Horizontal Rear Extension Timloc. This strong, reliable product is designed to fit into the lower rear opening of the telescopic underfloor ventilator and effectively accommodate cavity widths between 50-150mm, or internal walls of up to 200mm thickness. With its simple installation process and durable construction, this extension is the perfect addition for a professional ventilation system for your home or business.