Hello, I have used the Max 2K primer in the , which was recommended by my local Autobody/Paint supplier, and am very happy with the results. It is great for small areas and save allot of time and work with mixing and cleaning equipment. As stated in a previous reply their is a button inserted into the cap. First you want to shake the can well to mix the base, remove the button and place it on the plunger located on the bottom of the can. Place the cap back on top and turn upside down on a solid surface.Punch the button after it is in place this will release the catalyst, all you do now is shake the can some more. It does have a limited shelf life once mixed but I have always used up what was in the can. This product really deserves a . Good luck on your project.....Ed