Review on High-Temperature Spark Plug Boot Shields - 1800 Degree Heat Shield Insulator Sleeve for Car and Truck, 6 inch Spark Plug Wire Boots (Pack of 8) in Titanium Finish by Ray Richards

These cases are not of good quality. As others have said, they don't fit wires well (10mm), although you can open the ring sewn into the material (it's cut) and then insert without cutting the fabric. One of the biggest issues is aesthetics. Even though you can wear them over boots, the color (mine "was" red) is now entirely off the product and on your hands. The one I was able to partially save had the color disappear after 1 week of walking maybe once a day. Don't buy this. Now I'm looking for a quality set but I threw this one away. They looked like a joke on a real or even decommissioned engine.