So you've saved a lot of money for Kirby and you buy him belts at the grocery store or some fakes at your local vacuum store? Spend a little more and get a quality original Kirby belt. It will last longer and keep your Kirby performing the same as when it was new. Change the belt every 8-10 months for best results as it will stretch whether it's in use or just sitting, and a tight belt will slip meaning you won't get the full cleaning power that it should should. Professional advice, with every belt. It takes a few extra minutes to switch, and a pair of scissors to snip off all the hair and thread that has wrapped around your brush roll will do a much better job of cleaning. Once installed, make sure the grid markings on both ends of your roller are facing you the same way.