A premium #219 O-ring chain — the standard chain pitch for most racing karts. The O-rings seal grease between each pin and bushing, which keeps the chain lubricated internally and slows wear compared to a non-O-ring chain of the same size.
Per the manufacturer's spec, the side bars are SAE 1055 (or equivalent), the pins are chromized SAE 4340 (or equivalent), and the bushings are SAE 8620 (or equivalent) — all sensible steel grades for those roles — and the manufacturer rates the chain's breakage point at roughly 2,675 lbf.
