Acrylonitrile butaiene styrene, or ABS, (chemical formula (C8H8· C4H6·C3H3N)n) is a common thermoplastic used to make light, rigid, molded products such as piping, musical instruments (most notably recorders and plastic clarinets), golf club heads (used for its good shock absorbance), automotive body parts, wheel covers, enclosures, protective head gear, vballs [reusable paintballs], and toys including LEGO bricks. In plumbing, ABS pipes are the black pipes (PVC pipes are white) and also in Plastic Pressure Pipe Systems. ABS plastic ground down to an average diameter of less than 1 micrometer is used as the colorant in some tattoo inks. Tattoo inks that use ABS are extremely vivid. This vividness is the most obvious indicator that the ink contains ABS, as tattoo inks rarely list their ingredients.