Main Crank Pulley for Mitsubishi Legnum VR4 Galant VR4 also called a harmonic balancer/damper These are prone to the rubber section perishing and the 2 parts separating (This is not good for your engine) See HERE Total failure can result in destroying your crank angle sensor and can if it hits the propeller plate hard enough chop right through the cambelt in the process! Exploded Diagram HERE
Mitsubishi Part Number MD316782