These Nicro Ventilation Flexible PVC Clamshell Vents are durable and resilient. The soft, flexible PVC Clamshell Vents from Nicro Ventilation are safer than metal or other types of rigid vents. Due to their soft, flexible nature these vents deform if accidentally stepped on and then spring back to shape. You also dont have to worry about your jib sheet catching on these vents so there is no need to remove them before sailing. Typically used to cover bilge blower hose opening. Key Features Made out of Flexible PVC One year warranty