I don't know why this is called a cleaning brush for Clarke whistles. It is a cleaning brush for ALL (non-low) whistles. And they do have to be cleaned, for debris builds up in the over years. Until I saw this product listed, I didn't even know that there were cleaning brushes for whistles. This one, with its nylon bristles, works wonderfully well I was wondering why my whistle was sounding so raspy. It sounds much better now, after being cleaned with this terrific product.. I'll be forever grateful to Amazon for introducing me to this essential item.