Pack of 20, durable and discrete 1m long (2 x 500mm) interlocking opver fasica vents providing 25mm continuous eaves ventilation to encourage airflow throughout the roof system. Allows the roof to 'breathe' and discourages birds and large insects. Each lightweight polypropylene vent features stop beads that simplify the fitting to top edge of fascia board and integral nail holes for consistent and secure fixings. Inadequate ventilation in the roof space encourages moisture, which can damage roof timbers. All new-build properties must have continuous ventilation at eaves level to avoid damp and condensation within the roof void and to comply with Building Regulations. This 25mm capacity eaves vent is recommended for warm roofs, flat roofs and roof with pitch less than 14° and provides the equivalent of a continuous 25mm opening. The 10mm capacity vent provides the equivalent of a continuous 10mm opening and should be chosen for conventional cold roofs.