8407.90.10.10 - Less than 4,476 W

This HTS category, 8407.90.10.10, specifically classifies spark-ignition internal combustion piston engines that are intended for installation in agricultural or horticultural machinery or equipment, and importantly, have a power output of less than 4,476 Watts (or less than 37.3 kilowatts). These engines are typically smaller, lightweight, and designed for powering equipment such as rototillers, cultivators, small generators used in agricultural settings, or other specialized horticultural tools where a compact and efficient power source is required. The "less than 4,476 W" criterion is a key differentiator for classification within this subcategory.

This classification is distinguished from its sibling category, 8407.90.10.20, which covers "Other" spark-ignition engines for agricultural or horticultural machinery that do not meet the power limitation of this specific subcategory. Therefore, if an engine is designed for agricultural or horticultural use and its power output exceeds 4,476 Watts, it would fall under the "Other" sibling category. The primary distinction lies in the precise power output of the engine, with this category focusing on lower-powered units.

As this is a leaf node in the HTS classification, there are no further subcategories. The classification is finalized at this point based on the engine type (spark-ignition, reciprocating or rotary internal combustion piston engine), its intended application (installation in agricultural or horticultural machinery or equipment), and its power output (less than 4,476 W). Classification hinges on the accurate determination of these specific attributes.