Types of towing equipment
Truck with lifting platform
Five general types of tow trucks are in common use, generally based on the type or size of the vehicle being towed:
Boom: Use an adjustable boom with a winch to retrieve vehicles from a ditch, on an embankment, or anywhere the vehicle cannot be safely reached when reversing. Some booms are fixed, some use heavy swivel A-frames, others are equipped with hydraulic telescopic tubes. The heavier types of boom can rotate, effectively transforming the crane into a kind of mobile crane, called a “rotator,” and are generally reserved for heavy vehicle accidents.
 In the past, truck cranes used a “hook and chain” system in which the chains were wrapped around the chassis or axle of the vehicle and then lifted with a winch. A tow bar with heavy rubber mats connects the truck and the vehicle, so it can be towed on the other axle. The “harnesses” and “belt lifters” are an evolution, with rubber straps replacing part of the chains.    Harnesses are not widely used today because they can scratch car bumpers. But they are sometimes used for towing vehicles that have been in an accident or are missing one or two of the front or rear wheels or for pickup trucks and other vehicles with steel bumpers. All-wheel drive equipped cars cannot be towed with the harness as it can cause problems with the car’s transmission. 
Wheel lift in retracted position
Wheel lift (also called “eyeglass lift” or “bottom lift”) – Evolved from hook and chain technology to produce a large metal yoke that can be mounted under the front or rear wheels to support them, drawing the end front or rear of the vehicle lifted off the ground by means of a pneumatic or hydraulic hoist to allow it to be towed. This device generally raises the drive wheels of the vehicle (that is, the front wheels if it is front wheel drive, the rear wheels if it is rear wheel drive) by touching only the tires.  The wheel lift was designed by Arthur W. Nelson of Weld Built Body Co. in 1967.  The name show lift is common in Europe; the crib resembles a pair of square spectacles (spectacles). Medium and heavy trucks use a variant, “underlift” or “chassis lift”, which lifts the axle or frame instead of the wheels. Forklifts may have adapters that can also lift the frame. 
Integrated (also called “Self Loader”, “Snatcher”, “Quick Pick” or “Repo Truck”): arm and wheel lift integrated into one unit. It is used in light trucks to recover vehicles or move illegally parked vehicles. Most have equipment controls within the crane cab to allow for quick recovery without the inconvenience of exiting the truck to dock the vehicle.   Heavy duty trucks with integrated lift are also manufactured.
Platform with lifting wheels
Flat floor (also called “kickback”, “skid” or “tilt tray”) – The entire rear of the truck is equipped with a floor that can be hydraulically tilted back to ground level, allowing the vehicle to be placed on its own force or pulled by a winch.  Because they carry the vehicle instead of towing, they can be used in a completely immobile vehicle; in the United States they are used to transport cars seriously damaged by accidents.
Raise the floor
Raise the floor: One arm uses a wheel lift frame to lift the vehicle vertically and load it on the floor. Used in Europe, this truck can remove parallel parked vehicles.
These are the most common arrangements, but they are by no means exclusive, as there are platform units that offer a wheel lift, boom trucks that can retrieve but not tow, and wheel lift units that offer a boom combination. sling.