Replacement Filter Element, 18 Inch 3.0 Micron Synthetic Element, For Use With KF30, KF50, KC50, MKF50, KC65, KFH50, 2K9, 3K9, KF3, KL3, RT, KTK Series Housings

Same element covers both. The KKZ3 is listed for use across the KF30, KF50, KC50, MKF50, KC65, KFH50, 2K9, 3K9, KF3, KL3, RT, and KTK series housings, so you're not buying separate elements for each unit. The 18-inch length and Buna-N seal are consistent across that whole housing family, which makes stocking replacements a lot simpler when you've got multiple units running.

Yes, this replacement filter element is designed for use with KF3 series housings, as well as KF30, KF50, KC50, MKF50, KC65, KFH50, 2K9, 3K9, KL3, RT, and KTK housings.