Flywheels store and release rotational energy in engines and presses, while pulleys and pulley blocks redirect or multiply mechanical force in lifting, conveying, and tensioning systems — giving this heading relevance across construction equipment, marine, and industrial machinery sectors. Material and size differentiate commercial grades: cast-iron flywheels for large reciprocating engines versus lightweight composite pulleys for high-speed conveyors occupy very different market tiers. Importers should confirm whether articles are classified as complete assemblies or as parts, since that distinction can shift the applicable duty treatment.

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