7 String Set! FU-Tone Titanium insert blocks are made from the highest grade titanium available. There is another brand of titanium saddles out there that are made from a very low grade of titanium with a psi rating of 40,000 lbs. FU-Tone titanium blocks are rated at 140,000 lbs! Are you tired of your little black insert blocks cracking or expanding and getting stuck in the saddles? For the ultimate in performance and tonal response, this is a very easy upgrade to install.