The features of the HYFIRE 6EZ and HYFIRE 6EZ RPML are the same, with one exception: the HYFIRE 6EZ RPML includes a single stage RPM limiter. You can set various RPM limits using switches that are accessible through the rectangular cut-out in the end bracket. See page 4 of this instruction form for more information about the rev limiting features of the HYFIRE 6EZ RPML.