8412.21.00.45 - Telescoping

This HTS subcategory, 8412.21.00.45, specifically classifies telescoping hydraulic cylinders. These are a type of linear acting hydraulic motor characterized by their multi-stage, extending and retracting piston rod assembly, which allows for a longer stroke than a conventional cylinder of the same retracted length. They are designed to convert hydraulic fluid pressure into linear mechanical force and motion.

This category is distinguished from its sibling, 8412.21.00.60 "Rodless," which covers hydraulic cylinders where the linear motion is achieved without an external piston rod, typically employing a band, cable, or internal carriage system. The key differentiator here is the presence of a telescoping rod assembly for stroke extension in this category, as opposed to the absence of an external rod in rodless designs.

As this classification represents a leaf node within the HTS, there are no further subcategories. Therefore, classification into 8412.21.00.45 is determined by the presence of the telescoping rod feature, in conjunction with the product meeting the broader criteria for hydraulic power engines and motors, linear acting cylinders, and being of the "other" designation within that specific branch of the tariff.