40mm patented granite block.

It is designed to enhance and strengthen the sound of your tremolo-equipped instrument across the entire audio spectrum. These blocks are crafted from Volcano Black Absolute Granite, the compression strength of which is 19,000 psi/130,000 kpa and the tension strength of which is 700 psi/4,800 kpa; this is the 4th densest material on earth, just behind Diamond, Carbon and Quartz! Comes with stainless steel sustain block mounting screws and grounding wire.