Toro Groundsmaster 4500-D Operator's Manual page 18

Weight Gauge
Indicates when the seat is adjusted to your weight (Figure
13). You can make height adjustments by positioning the
suspension within the range of the green region.
Weight-Adjusting Lever
Adjust for your weight (Figure 13). Pull up the lever to
increase the air pressure, and push down the lever to decrease
the air pressure. You attain the proper adjustment when the
weight gauge is in the green region.
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