A bike lock is a security device used to secure bicycles and prevent theft. It typically consists of a strong, durable material that can withstand cutting or tampering. Common types of bike locks include U-locks, chain locks, and cable locks, each offering different levels of security and convenience. Using a bike lock properly is essential for effective protection. Cyclists should lock their bikes to a sturdy, immovable object, ensuring that both the frame and wheels are secured. Additionally, choosing a high-quality lock can deter thieves and reduce the risk of bike theft in urban areas.