CRF100 '93 - '22 XR100 '93 - '22 Choose Model Rev Box (CRF100 '93 - '22, XR100 '93 - '22) Rev Box (CRF230F '03 - '14, CRF150F '03 - '05) Add to cart $69.95 Eliminates the 9800 rpm rev limiter and provides a hotter advance curve. Direct replacement for the OEM CDI ignition box