Bionaire 110 Electret Filter.

Bionaire 110 Electret Filter is a Genuine OEM Bionaire Filter.
110 Electret Filter fits BT1000, BT1000C.
Bionaire 110 Electret Filter traps microscopic dust, allergens, tobacco smoke.
Filter Dimensions, inch. 27 x 13 x 0.2.
Filter's Lifetime: 3 months on average.
Comes 1 filter per pack.