DID Motocross Chain - Made in Japan Don't settle for anything less. Used by Ryan Villopoto to win 4 AMA SX titles All D.I.D 'ER' chains are designed exclusively for racing. 520ERT3 is used by the top factory SX and MX Teams to win races. 520MX chain has higher tensile strength for maximum performance and is ideal for muddy and sandy conditions. 520VT2 for offroad applications where a sealed chain is preferred, D.I.D's 520VT2 X-Ring chain provides excellent low friction high performance. D.I.D's exclusive SDH pin treatment is featured on the 520ERT2, 520 MX, 520DZ and all NZ Series chains. Fits: KTM 50 SX 2003-2011 50 SX MINI 2010