Provides the best moisture and air infiltration seal between the rafter vent and wall top plate. Works with Durovent and Provent to provide a moisture impervious vent and block system.  Ordered by the pack (10 Windblocks per pack).

• Polyboard material is waterproof and prevents moisture infiltration
• Secures vent in place eliminating blow-out during construction
• Blocks moisture from exterior and acts as an insulation stop for interior