In the video, a person is seen using a blue pen to measure the size of a screw. The pen is placed on the screw, and the person adjusts the pen to align with the numbers on the screw. The person then uses the pen to measure the size of the screw, which is 0.001 inches. The video provides a close-up view of the measurement process, allowing viewers to see the details of the pen and the screw. The person's hand is steady, and they appear to be experienced in using the pen to measure the size of the screw. The video is informative and useful for anyone interested in learning how to measure screw sizes accurately.