The FROTuB37 is a 37mm tungsten sustain block made to bolt directly onto a Floyd Rose Original series base plate in place of the stock block. The sustain block is the mass anchor for the whole bridge assembly — it is what the strings terminate into below the plate, and its density determines how much of that vibration stays in the bridge rather than bleeding off through the tremolo springs.

Before ordering, measure your body cavity and your existing block. The replacement block has to clear the cavity at full dive — too long and the block bottoms out before the arm travels; too short and the springs sit at a shallow angle that pulls tune. The mounting screw pattern also has to match your base plate exactly. This block is built to Original series dimensions, not to the specifications of other Floyd Rose variants or licensed copies. If your current bridge is not an Original series unit, do not assume the bolt pattern is the same.

Tungsten is denser than brass and denser than titanium. Higher density in the same physical envelope means more mass without a larger block — which matters because most spring cavities are sized around the stock block footprint. Tungsten is also harder than brass, steel, and titanium. The combination of high density and hardness affects attack character: harder, denser materials absorb less string energy and return it more directly compared to softer metals such as brass.

If you are not certain this is the right block for your bridge, send us the make, model and year of your guitar and we will confirm before you order.