Just my .02 all Prop Lab's are certainly not the same. The whole concept is too bring the prop as perfectly into spec. as it can be, and then tuning the rake, pitch, and Dia. To get what you need out of set of props. Mercury developed these props, and they have the expertise to turn out a stellar product. I have never broken a prop blade, except by striking something. Mercury Lab is the best. Dennis Cavanaugh will never steer you wrong.