Hitachi CG40EK Owner's Manual page 17

Spark arrestor
If your unit comes with spark arrestor screen
and yet your local regulation requires use of
spark arrestor for prevention against a possible
fire, please attach it to the muffler by removing
muffler protector and other related parts. (The
spark arrestor meets the regulation of SAE
J335-SEP90 and CSA CAN3-Z62 1-M77.)
GB-15