8413.91.90.55 - Fluid end blocks

This HTS classification, 8413.91.90.55, specifically designates "Fluid end blocks" which are essential components of hydraulic fluid power pumps. These blocks typically house the valves and passages through which hydraulic fluid is directed for pumping operations. They are manufactured from robust materials to withstand high pressures and the abrasive nature of hydraulic fluids, and their primary function is to facilitate the controlled movement of fluid within the pump assembly.

Distinguishing this category from its sibling, 8413.91.90.60 ("Other"), is crucial. While "Other" encompasses a broader range of hydraulic pump parts that are not specifically enumerated, 8413.91.90.55 is reserved for the distinct component known as the fluid end block. This implies that components like pump casings, shafts, or other internal mechanisms would likely fall under the "Other" category, unless they are explicitly defined as a fluid end block.

As this is a leaf node within the HTS database, there are no further subcategories under 8413.91.90.55. Classification within this category hinges on the precise identification of the part as a fluid end block, a critical structural and functional element of hydraulic pumps, designed to manage the intake and discharge of hydraulic fluid.