Replacement Air Filter Assembly (housing and filter) for Iwata Workshop IWC28S Quiet Air Compressor. The filter protects the motor from dust and particulates and must be inspected regularly and replaced when necessary. To inspect the filter, remove the housing cap and pull out the internal filter. If it is dirty or damaged, it is time to replace the internal filter (Item #IWC152). Damage to the compressor motor may occur if air filter becomes clogged so we recommend keeping extra filters on hand.