What devices are attached to the roof edges to catch rainwater?

Rain gutters are long, hollow devices attached to the roof edges. Their primary purpose is to catch rainwater and direct it away from your foundation. For a house to be complete, it needs a gutter system to function properly. Your gutters are responsible for water management. During a storm, they effectively channel water flow from your roof, through the downspouts, and direct it to appropriate areas outside the home.

Source: Garlock-French Roofing