Enduro is a racing format in which the descents are timed, but you still have to pedal yourself around the course between them. That means these bikes are designed to perform exceptionally well down steep and difficult trails, but are still light and efficient enough to pedal back to the top.
Enduro bikes tend to have more travel than typical trail bikes, and are almost exclusively full-suspension. Most use around 160 to 180mm of travel at either end, paired with tough wheels and reinforced tyres.
The suspension units they use are usually still air-sprung, but tend to be heavier-duty with a wide range of damping adjustments to tune their downhill performance. However, there’s a growing trend towards builds featuring coil shocks for their lower maintenance and riding consistency.