Review on 40Pcs Copper Nickel-Plated Schrader Valve Cores + 20Pcs O-Ring Seal Valve Stem Caps + 3 Dual Single Head Valve Core Remover Tool Tire Repair Tools - Valve Core Removal Set by Chef Deane

First, I've been a mechanic for 16 years and I'm well versed in the procedure and installation of valve cores. They're so cheaply made and no matter how clean or tight the valves are, they're still leaking. It had to try every core to find 2 that actually worked and didn't lose air. And those that held air buckled after being filled with an air intake. I will neither buy nor recommend them. I would say spend the extra $2 on a higher quality product and save yourself a headache and a lot of time.