A highly durable solvent borne highly translucent satin woodstain cetol filter 7 is a highly translucent satin exterior woodstain for windows and doors it can be used as a maintenance coat for existing woodstain systems or over a base stain of cetol hls on new or bare timbers cetol filter 7 is an exterior woodstain for windows and doors either as a one coat maintenance application for existing woodstain systems or two coats over a base stain of cetol hls on new or bare timbers its advanced uv li