Travelcard Zone 4 is part of the London transport system, specifically designed for travel within the Greater London area. It includes various neighborhoods and suburbs, providing access to key locations outside the central zones. This zone is popular for commuters and visitors who need to travel to areas like Walthamstow, Bromley, and Croydon. Travelcards for Zone 4 allow unlimited travel on London Underground, London Overground, and National Rail services within the zone. They can be purchased for different durations, such as daily, weekly, or monthly, making them a flexible option for both residents and tourists exploring the outskirts of London.