Included parts:

Dtune Brand New Diesel dump valves are universal for most turbo diesel cars.
All all our diesel electrical dump valves are thoroughly tested to make sure the valve
opens and closes properly at the set rates on the springs.
Materials used for making BOV are high quality aluminum alloy

China Diesel Dump Valve - DTune Racing Performance Parts

[What is a Dump Valve?]
Most production turbocharged engines are fitted with a dump valve. This is to vent away excessive turbocharger boost pressure when the throttle is closed.
All Sierra Cosworth and the original large turbo Escort Cosworth models use the same dump valve. The turbocharger fitted to the latest Escort Cosworth has its own integral unit.
The dump valve is the black plastic saucepan shaped object that you will see connected between the intercooler and the air inlet hose to the turbocharger. You will also see a small hose leading from the top of the valve to the inlet plenim on the engine. Inside the valve is a rubber diaphragm and a steel spring, with a small insert to support the diaphragm where it seats against the dump valve body.

The dump valve has basically two operating conditions; throttle open, and throttle closed. When the throttle is open, the boost pressure coming into the valve from below the diaphragm is equalled by the pressure onto the top of the diaphragm that comes via the small hose from the engine plenim chamber. As the pressures are equal, the spring holds the diaphragm onto its seat, and prevents the pressure venting away. When the throttle is closed, the pressure coming into the top of the valve is significantly reduced, (often to a vacuum), and the pressure below the diaphram lifts it away from its seat, allowing the excess pressure to vent away. As the throttle is reopened, the pressures again equalise, the spring pushes the diaphragm onto its seat, and the boost pressure cannot vent away.

[What about turbo diesel dump valves?]
If you are asking if you can use a petrol dump valve in your turbo diesel car, the answer is NO. Petrol dump valves are useless to your car because diesel cars are built differently from petrol turbo cars.

Turbo diesel cars are not equipped with the same throttle plates as in a petrol turbo car that controls the engine speed. In a diesel car, the engine needs all the air that the turbo charger can give it. It thrives on compressed air for its cylinders to function optimally. A diesel dump valve will only provide the sound but no performance gain.

Diesel dump valves therefore, are not really needed because your turbo diesel car loves the high-pressure build-up. Should you insist on installing a diesel dump valve in your turbo diesel car, you only get the 'woosh' sound when you shift gears.

There isn't much point in arguing about the necessity of the dump valves in a turbo diesel car. You could install it if you want the performance sound but its down to individual choice and preference as not everyone who drives a turbo diesel wants to install a dump valve