This blade guard measures 6.5" or about 165mm and will fit most knives this size including long pettys, paring knives and utility knives. Also measures 1" wide. It's open on one side so you can easily slide the knife into the guard and it will hold it. This plastic is hard, food safe and durable. Great for taking your knives to work or protecting them when putting them in your drawer for quick and inexpensive storage. They're also dishwasher safe.