Review on 🔧 Aupoko R134A R12 Valve Core Quick Remover Installer: Adjustable High and Low Pressure Tool Set, 2 Pack (Red/Blue) by Brandon Daughenbaugh

This product works as it should. For people who say they aren't, 99% are probably using the tool incorrectly. As you begin to unscrew the valve core, pressure is released into the tool. You have to make sure the plunger doesn't squeeze you into your hand or it will loosen the core. Instead, push the plunger further into the tool and turn counter-clockwise an additional 3-4 turns until the core is completely out of the valve. You can then close the valve, remove the back of the tool, and remove the old core. For the record, I used it on a 99-07 Silverado/Sierra/Tahoe, every GM product that year, and it worked great.