silkagard black limestone sealer...protects against the effects of weathering.petrol spills and green growth.... silkagard black limestone is a high performance.surface coating that is specially formulated to make tired black limestone look like new the of black limestone that is left out in the open. exposed to UV light and rainfall tends to fade to a light grey over time once applied black limestone sealer provides a tough durable low sheen finish that protects the surface against the effects of weathering spillages and green growth
eBay