Aerial Lifting Devices are a mechanical devices used to provide access for people or equipment to inaccessible areas, usually a height. They are generally used for temporary, flexible access purposes such as maintenance and construction work or by firefighters for emergency access, which distinguishes them from permanent access equipment like elevators. They are usually capable of being set up and operated by a single person. Regardless of the task they are used for, aerial work platforms may provide additional features beyond transport and access, including being equipped with electrical outlets or compressed air connectors for power tools. They may also be equipped with specialist's equipment, such as customization for carrying frames for window glass, etc. Types include Boom Lifts, Trailer Mounted Booms, Scissor Lifts, Slab Scissor Lifts, Rough Terrain Scissor Lifts, Aerial Work Platforms, and Vertical Mast Lifts. The range for lifting heights is 10 feet to over 210 feet. They are designed to lift limited weights — usually less than a ton — which distinguishes them from most types of cranes. Maximum operating weight rarely exceeds 1,000 lbs.