XTA1207 Features: * Filter cartridge * Improved performance * Easy maintenance * Unique cartridge design: Round modern design, continuous flush performance, improved biological filtration * Improved flow rates and multi-density floss * Medium fits whisper ex20 Includes: * Timestrip cartridge change indicators included Options: * Available in several sizes Dimensions: * Medium / 2 Pack Dimensions: 1.5" H x 4.75" W x 8" D * Large / 2 Pack Dimensions: 1.75" H x 5" W x 10" D * Medium / 4 Pack Dimensions: 6" H x 4.25" W x 3.75" D