From REDS Racing:
REDS has introduced two new options for your Quattro Clutch system. These new front plates allow for more pre-tension on the springs and better snap, typically used in a Truggy application.
They are available in two versions XH and XXH, extra hard and 2 X hard respectively. This allows you to add two more adjustments to REDS Quattro Clucth System (standard adjustments available are L and H).
We recommend to use the NEW PRE -TENSION TOOL to facilitate assembling. The PRE -TENSION TOOL can also be used with Quattro Clutch standard front plate.