Identifying the correct Harmonized System (HS) Code is critical to determine duty rates and regulatory requirements. Generally, sensors fall under Chapter 90 (Optical, measuring, checking, precision instruments) or Chapter 85 (Electrical machinery). For example, HS 9025 is for temperature sensors, while HS 9026 covers sensors for measuring flow or level of liquids. Always verify the technical working principle (e.g., capacitive, inductive, or optical) with your supplier, as a wrong code can lead to customs delays, fines, or seizure of goods.