YMG Holmes 600R on wikipadia "Tow truck"

YMG are specialist of towing trucks and equipment, we do not search what Towing truck is on web normally, yet what my friend found on Wikipedia is YMG Towing truck picture that Holmes 600R truck as mentioned "Boom truck with underlift" is belong to YMG partner Yamaguchi-Wrecker Co, Ltd.

Tow truck

A tow truck (also called a wrecker, a breakdown truck, recovery vehicle or a breakdown lorry) is a truck used to move disabled, improperly parked, impounded, or otherwise indisposed motor vehicles. This may involve recovering a vehicle damaged in an accident, returning one to a drivable surface in a mishap or inclement weather, or towing or transporting one via flatbed to a repair shop or other location.

A tow truck is distinct from a motor carrier that moves multiple new or used vehicles simultaneously in routine transport operations.

Types of towing equipment

Five general types of tow truck are in common usage, usually based on the type or size of vehicle to be towed:

Boom – use an adjustable boom with a winch to recover vehicles from a ditch, over an embankment, or any place the vehicle cannot be safely reach backing-up. Some booms are fixed, some heavy pivoting A-frames, others hydraulic-powered telescoping tubes. In the past boom trucks used a "hook and chain" system where chains are looped around the vehicle frame or axle, then lifted by a boom winch. A towbar with heavy rubberized mats connects the truck and vehicle, so it can be towed on its other axle. "Slings" and "belt lifts" are an evolution, with rubber straps replacing part of the chains.[2][3][4] Slings are not used much today because they can scratch the bumpers of cars. But they are sometimes used for towing vehicles that have been in an accident or have one or two of the front or rear wheels missing or for pickup trucks and other vehicles that have steel bumpers. Cars equipped with all-wheel drive cannot be towed with a sling, since it can cause problems with the car's drivetrain.[5]
Wheel-Lift (also called a "spectacle lift") – evolved from the hook and chain technology to produce a large metal yoke that can be fitted under the front or rear wheels to cradle them, drawing the front or rear end of the vehicle clear of the ground by a pneumatic or hydraulic hoist so it can be towed. This apparatus generally picks up the drive wheels of the vehicle (i.e. the front wheels if it is front wheel drive, the rear wheels if it is rear wheel drive) touching only the tires.[3]The wheel lift was designed by Arthur W. Nelson of Weld Built Body Co. in 1967.[6] The name spectacle lift is common in Europe; the cradle resembles a pair of squared spectacles (eyeglasses). Medium and heavy trucks use a variation, the "underlift" or "chassis lift", which lifts the axle or frame instead of the wheels. Wheel-lift trucks can have adapters which can also lift the chassis.[2]
Integrated (also called a "Self Loader", "Snatcher", "Quick Pick" or "Repo Truck") – boom and wheel-lift integrated into one unit. Used in light duty trucks to repossess vehicles or move illegally parked vehicles. Most have controls for the apparatus inside the cab of the tow truck to make quick pickup possible without the inconvenience of exiting the truck to hook up the vehicle.[7][8]Heavy duty trucks are also manufactured with integrated lift.
Flatbed (also called a "rollback" or a "slide") – the entire back of the truck is fitted with a bed that can be hydraulically inclined and slid back to ground level, allowing the vehicle to be placed on it under its own power or pulled on by a winch.[9] Because they carry rather than tow the vehicle, it can be completely immobilized; in the US they are used to carry badly damaged cars from crashes.
Lift flatbed – a boom uses a wheel-lift frame to lift the vehicle vertically and load it on the bed. Used in Europe, this truck can remove vehicles that are parallel-parked.

These are the most common arrangements, but are by no means exclusive, as there are flatbed units that offer a wheel-lift, boom trucks that can recover but not tow, and wheel-lift units that offer a combination boom with sling.

(Reference : https://en.wikipedia.org/wiki/Tow_truck Picture: https://upload.wikimedia.org/wikipedia/commons/thumb/0/0a/Century_001.jpg/220px-Century_001.jpg