The dry powdered "Bars Leak" (used to be dry tablets) is the one often installed, at the factory. It can be used with antifreeze. After 5000 miles, it disapates. In fact it is recommended service on cadi engines.
The pellets in liquid, bottled Bars Leak, is not used at the factory, is more agressive and effective and, as I recall, should be used with straight water.
Years ago, a "Bars Leak" rep showed up at my shop and gave us a demonstration. I have often used it since. Not a cure-all, however.