This OSHA Table 1-compliant Dust Box Assembly features a filter cleaning mechanism and a HEPA filter. It retrofits onto the D25303D and attaches to the DWH303DH and the DWH304DH as a replacement filter assembly. The durable and clear high-capacity dust box allows the user to see when to empty. The high-efficiency HEPA filter removes 99. 97% of airborne particles 0. 3 microns or greater. Labels on the outside of the dust box call out the HEPA filter and the OSHA 1926. 1153 compliance.