A stainless steel ruler is a durable measuring tool, typically made from hardened stainless steel, with clear etched markings in both imperial (inch) and metric (millimeter) units, designed for accurate measurement, drawing straight lines, and marking in applications like machining, woodworking, and art and craft. Its metal construction makes it more durable than plastic rulers, offering a rigid or sometimes slightly flexible bar with easy-to-read graduations for long life and precision.