Product review (3 stars): Here's a better Description
This filter is a replacement for the Holmes HWF100.
The filter works with Bionaire humidifier models BCM4600, BCM645, BCM646, BMC5520, BCM5520RC, BCM5521, BCM4600, BCM5520RCU, BCM6000, BCM6010, BCM6010RC, BCM6610RC, BCM7203, BCM7203RC, BCM7204, BCM7205, BCM7207, BCM7305, BCM7305RCB, BCM-7305RC, BCM7306, and BCM7307. It also fits Holmes humidifier models HM729, HM729G, HM630, HM7204, HM7305/RC, HM7306, HM6000, HM6000RC, HM6600, HM6005HD, and HM4600/HD. The two-pack of humidifier filters measures approximately 5-3/5 by 4 by 7-4/5 inches.
There are two filters in the box and an installation clip is included.