SmokeBlock filters are compatible with the following Blue air purifiers:
Blue Pure 211+/221 Series: 211+/Blue 221 and 211+ Auto/Blue 3610.
Blue Pure 311 Auto/3410 Series: 311 Auto/Blue 3410.
Blue Pure 411 series/Joy S: 411, 411+/Joy S, and 411 Auto/Blue 3210.