Standard 1 micron replacement filter for for the CT 22 and CT 33. Measured in microns wood dust is particularly troublesome to remove from an environment once it is airborne. The best way to minimize the effects of dust created during fabrication is to use tools that are designed with dust extraction in mind. When partnered with a good dust extractor with proper filtration you will be able to eliminate the majority of the dust created at the source before it is ever released into your environment. Designed to trap particles down to 1 micron while maintaining airflow allowing you to reach full capacity without clogging or caking. Includes 2 Standard Main Filter Elements.