In the video, a person is seen using a tool to measure the size of a bullet. The tool is a dial indicator, which is a precision instrument used to measure small distances or variations in surface levelness. The person places the bullet on the dial indicator and adjusts the tool to ensure that the needle is at the correct position. The dial indicator is mounted on a stand, which provides stability and allows the person to make precise measurements. The person's hands are visible in the video, and they appear to be experienced in using the tool, as they handle it with confidence and precision. The video provides a close-up view of the tool and the bullet, allowing the viewer to see the details of the measurement process.