This is our "Monster" thumbdisk made in Naval Brass. Naval Brass is more resistant to corrosion and wear than normal brass, so it will patina more slowly and be slightly more wear resistant. Our Monster disks are 25% larger then the stock model (@1/2 in diameter compared to the factory 3/8in diameter), but without protruding past the scales. Drop in fit. This is THE answer to those hard to open knives! *Does NOT fit the Hinderer FireTac or ZT-0620/30/40 knives!* (Diamond Knurl Shown)