Bruce, I cant remember the exact specs offhand,they are manufactured by Kobe.. the (60) denotes the carbon content, in short, the Spring Rate Sensitivity60 was shown in a series of tests to only have one premature failure compared to 5160's 4 failures out of 8 tests ran, while the UHS1900 doubled the stress tests before it had one premature. both of the steels are extremely tough while exhibiting good wear resistance .. so there are some great steels out there, but that's where science stops and here is where the magic starts, sure you or I could make a blade that would most definitely compete for the "toughest baddest thing out there" but with the cost, the time, and general frustration of just doing it, makes it a welcome pleasure to sit at a computer and order Bussekin blades, that are already at the top of the chain, so when you say (Busse) the best in the world, I have 100% no argument there at all, because with the warranty and the quality they have, that statement couldn't be more true. .....You, I, and the rest of the Dogs are most definitely in the right place!!