Honda HHT31S Owner's Manual page 59

Air Index
An Air Index Information hang tag/label is applied to engines certified to an emission durability time
period in accordance with the requirements of the California Air Resources Board.
The bar graph is intended to provide you, our customer, the ability to compare the emissions
performance of available engines. The lower the Air Index, the less pollution.
The durability description is intended to provide you with information relating the engine's emission
durability period. The descriptive term indicates the useful life period for the engine's emission control
system. See your Emission Control System Warranty for additional information.
Descriptive Term
Moderate
Intermediate
Extended
The Air Index Information hang tag/label must remain on the trimmer/brush cutter until it is sold.
Remove the hang tag before operating the trimmer/brush cutter.
TECHNICAL & CONSUMER INFORMATION
Applicable to Emissions Durability Period
50 hours (0–65 cc)
125 hours (greater than 65 cc)
125 hours (0–65 cc)
250 hours (greater than 65 cc)
300 hours (0–65 cc)
500 hours (greater than 65 cc)
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