focus on robust materials (HNBR, NBR) for downhole conditions, high wear/temperature resistance (up to 300°F+), specific dimensions for tool OD/ID (e.g., 1.875" OD), durometer (70-90A), and design features like retrievability for MWD/logging tools, ensuring protection against shock, vibration, and mud erosion while fitting casing sizes. Key specs include material grade, size (OD/ID), hardness, temperature range, and compatibility with drilling fluids.