The new DID 520DZ2 is a high performance chain available at an affordable price. Designed to meet demands of the most gruelling MX tracks, the 520DZ2 is designed to meet the challenge. Now greatly updated with D.I.D's exclusive SDH technology. D.I.D’s exclusive SDH pin treatment is another secret behind their winning performance. The SDH pin treatment creates an extremely hard chromium carbide layer on the pin surface which increases chain life and at the same time the pins inner core remains soft to absorb the tremendous shock loads of triple jumps without breaking.