Includes 2 belts * Fits all Lift-Off Bagless Models * Works with Model #s: 18Z6, 37604, 42209, 6860H, 37606, 89Q9, 6850 * When do I replace the belt? If the vacuum is not cleaning as well as it had before or the brush roll has stopped turning, you may have to change the belt. To change the belt, please refer to your models user guide for installation instructions.