Anti-bacterial treated; traps minerals. Fits most holmes humidifiers. Metal reinforcement. Adds rigidity to shape of the wick filter when moistened. Also adds stability with today s softer more absorbent paper. Prevents slumping or sagging over time or when wet. Helps maintain the humidifier s designed output. Wick filter fits holmes hm1800 1840 1845 1850 1851 1855 1865 1888 1889 1895 1975 2059 2060w 2090 3000 3850 note 3800 3850 needs 3 fltrs 4000 needs 2 filters hwf-65 ; sunbeam scm1895 1896 scm1866 sf206 ; white-westinghouse wwhm1840 2090ze wwh650 ; ge 106609 106663 106763; bionaire bcm-1845 1855 . Dimension - 16 x 8.5 x 11.5 in.. Item weight - 0.66 lbs.