9032.81.00 - Hydraulic and pneumatic

HTS code 9032.81.00 specifically classifies hydraulic and pneumatic automatic regulating or controlling instruments and apparatus. This category encompasses devices that utilize fluid pressure, whether liquid (hydraulic) or gas (pneumatic), to automatically adjust or maintain a desired operational condition. Examples include pressure regulators, flow controllers, and servo-valves that operate based on hydraulic or pneumatic principles.

This subcategory is distinct from its sibling, 9032.89, which covers "Other" automatic regulating or controlling instruments and apparatus not primarily functioning on hydraulic or pneumatic principles. While both fall under the broader category of "Other instruments and apparatus" within Chapter 90, 9032.81.00 is narrowly focused on systems driven by fluid power.

Within this classification, a further subdivision exists: 9032.81.00.80, designated for "Other" hydraulic and pneumatic instruments and apparatus. This hierarchical structure allows for the specific categorization of a wide array of fluid-powered control devices, separating them based on further defining characteristics or specific applications not captured by the general "hydraulic and pneumatic" designation.