The Montigo 4 Inch Inner Diameter Horizontal Termination without Mounting Frame is handy for your Montigo venting system. This 3-inch-long piece has a 4-inch inner and 7-inch outer diameter, making it easy to connect to your existing venting system. It's designed for horizontal terminations, and while it doesn't come with a mounting frame, it's compatible with either Montigo MSR or MOSR mounting frames for easy installation. This convenient termination accessory enhances your Montigo venting system for smooth and efficient airflow.