The Smart Tennis Hub is Tennis Machine SG's 24/7 self-service smart locker for tennis: a cabinet at or near the courts with a touchscreen and five compartments, holding a professional ball machine, charged batteries, 130+ balls, a transport cart, a ball picker and optional racquets. You book online, collect everything with a six-digit pickup code, and the hub's sensors check the machine, battery, ball bag and racquets back in when you return them. There are no staff, no keys and no app to install to book.