Nickel-plated valve cores are commonly used in stem-mounted sensors. These cores are made of brass and coated with a layer of nickel to help prevent corrosion and improve durability. The nickel plating also provides a smooth surface that helps to create a tight seal between the valve core and the stem, which is important for accurate pressure measurements. Overall, nickel-plated valve cores are a reliable and long-lasting option for use in stem-mounted sensors.
Answer: brass