External Dust Extraction Device – The Crevice Nozzle is specially designed for accessing hard-to-reach areas. It is ideal for reaching into corners and grooves. The Crevice Nozzle connects to dust extractor tubes for Bosch dust extractors. External Dust Extraction Device Crevice Nozzle is specially designed for accessing hard-to-reach areas Ideal for reaching into corners and grooves Connects to dust extractor tubes for Bosch dust extractors