Just buy at this price.1. Not all flat or flat tires are caused by punctures. Some valve cores begin to leak over time due to aging or dirt particles. To identify a leaking core, simply remove the valve core cap and apply a soap and water mixture to the top of the valve stem. If it bubbles, your valve core is leaking. Simply remove the old valve core with this tool and replace it with one of the new valve cores.2. If you replace your valve stems every time, this tool will make it that much easier. Cut out the old stem and thread the new stem with this threading tool. Again, use a mixture of water and soap to lubricate. Most tire shops will charge $10 to $20 for these services. This tool costs less than two dollars.