if you want the probe that finds all three axis that will help you restart carves and etc. here is a link to the product that everyone is referring to.
to do all three axis you need more that just the touch plate. you will need something to generate the G-Code to touch off all three corners that can be recalculate for different bit sizes. this product also has a program that does that and stores the information for future use. this is the products everyone is talking about because it saves so much time having it all in one program.