The four-legged robot maintained a steady pace of around 9 minutes and 24 seconds per kilometer, with a top running speed of up to 6 meters per second. They were equipped with "half-marathon pacer" balloons to help runners maintain a scientifically optimized running rhythm.

According to Zhejiang Television, this marks the first time in international marathon history that robotic pacers have been used.

As previously reported by the Global Times, a larger robot, B2, took on the role of "cut-off pacers" for the half-marathon event, while a smaller one, known as Go2, served as companion pacers for the fun run.