A projector's air filter prevents dust from accumulating on the optical elements inside the projector. If you are replacing your lamp, it is a good time to replace your filter. Manufacturers' suggest replacing the filter when changing the lamp to ensure optimal performance. The ET-EMF510 filter is compatible with the PANASONIC PT-DS20K, PT-DS20KU, PT-DS20KE, PT-DS20E, PT-DS20U, PT-DS20KUL, PT-DS20KEL, PT-DS20EL, PT-DS20UL, PT-DS20K2U, PT-DW17K2U, PT-DZ16KU, PT-DZ21KU, PT-DS20KU, PT-DZ16K2U, PT-DZ16KU, PT-DW17K, PT-DW17KU, PT-DW17KE, PT-DW17E, PT-DW17U, PT-DW17KUL, PT-DW17KEL, PT-DW17EL, PT-DW17K2, PT-DZ16K, PT-DW17KU, PT-DW17KE, PT-DW17E, PT-DZ16U, PT-DZ16KUL, PT-DZ16KEL, PT-DZ16EL, PT-DZ16UL, PT-DZ16K2, PT-DZ21K, PT-DZ21K, PT-DZ21KU, PT-DZ21E, PT-DZ21U, PT-DZ21K, PT-DZ21K2, PT-DZ21K, PT-DZ21KU, PT-DZ21E, PT-DZ21U, PT-DW17K2E, PT-DW17K2J, PT-DW17K2U, PT-DW17UL projectors.