1998-99 Polaris Big Boss 500 6x6 Race-Driven O-Ring Chain 520-64L 72L 88L 116L 64L, 72L, 88L, 116L O Ring Chain Race-Driven O Ring Chain's tensile strength = 8200+ lbs. All chains include masterlink. O-Ring Chain helps keep the pins lubricated which reduces friction and helps the chain last longer. Fits 1998 1999 Polaris Big Boss 500 6x6