Protects against the spread of fire through the core drilling and prevents sound bridges: Schlüter-KERDI-DRAIN-ZBS offers approved fire protection in combination with the fire protection inserts KERDI-DRAIN-BS and KERDI-LINE-BS. That makes the conduit gasket the perfect fire protection supplement for the vertical floor drain set KERDI-DRAIN-BAV 50 GVB and for the vertical linear drainage KERDI-LINE-V 50 G2.