Can play a slow vibration, insulation, isolation effect

Inside diameter 4MM, can make the use of M4 type screw
Can be used to pump at the end of shock absorption, slow down the vibration of the pump running, other parts of the damping function can play at random.
Size: outside diameter 12mm* diameter 4mm* thickness 2.3mm
Product quantity: 8pcs/ bag
Material: silicone
Color: Black