This OSK complete timing gear set provides all the items needed to replace the timing chain assembly. This kit contains the following: Product Features:upper and lower timing chains,2 cam sprockets, crank sprocket,LH and RH guides for lower chain,top guide for upper chain (top guide not used on some engines; LH guide for upper chain is no longer required),upper and lower chain tensioners,front crank seal, and 2 cam sprocket retaining bolts. Timing cover gaskets are not used on this application; use the appropriate liquid gasket sealant instead. Order idler sprocket 13077-1E400 (Altima) or 13077-53F00 (240SX) separately.