Businesses in the watches category sell timepieces for everyday use, work, sport and formal occasions. Their ranges may include analogue and digital watches, quartz and mechanical models, smartwatches, children's watches and specialist designs such as diving or aviation watches. Customers can often choose from different case materials, strap styles, sizes and functions, including alarms, chronographs, date displays and activity tracking. Some retailers also stock watch straps, batteries, presentation boxes and other accessories. Many watch businesses provide aftercare and repair services, either on site or through specialist workshops. Work may include replacing batteries and straps, adjusting bracelets, repairing or servicing movements, restoring older watches and checking seals or water resistance. Services and expertise vary: some businesses concentrate on retail, while others specialise in watchmaking, repairs, vintage pieces or particular types of mechanism.