Thick-walled (3.6mm), case-hardened rocker shaft. Ideal replacement for a standard rocker shaft, which quickly shows wear on the underside. Performance engines with strong valve springs can even break standard rocker shafts, so you want the extra strength of this hi-spec version. Ref: C-AEG399, SEN0022HD.
Rocker alignment shims AEG0168 and AEG0169 are available to centralize the rocker on the valve.