In 1944-45, German V-2 missiles were launched from various sites to avoid Allied air attacks. The V-2 launch group had to be, therefore, highly mobile and capable of movement off the road. The firing of up to 8-12 missiles per day by some batteries showed the ruggedness in ingenuity of these units.
There were different types of specialized support vehicles in the V-2 launching units, such as rocket trailers, generators, pumps, command vehicles (Lw35222 and Lw35223 kits), and fuel bowsers (Lw35019 and Lw35020 kits).

The V-2 rockets used a multi-component fuel. The main engine worked on a mixture of A-Stoff (liquid oxygen), and B-Stoff (75% Alcohol).
In flight, the rocket engine was fed with the fuel by a 580 horsepower turbo-pump, which utilized its own two-component fuel - the Z-Stoff (a mixture of sodium permanganate with water) and T-Stoff (85% hydrogen peroxide).

To supply T-Stoff, a special Tankwagen (fuel bowser on Opel-Blitz schassis, Lw35019 kit), carrying 640 gallons of T-Stoff in aluminum container, was used.
It was equipped with a pump with a 66-gallon per minute capacity.
After the rocket was fuelled with A-Stoff (liquid oxygen), and if the ambient temperature was below 20C, there was a risk of freezing of the T-Stoff in the turbo-pump.

To delay freezing, a special device - Vorwarmer (heater) - was to be used to pre-heat T-Stoff before it enters the rocket.

The Vorwarmer consisted of cylindrical aluminum T-Stoff container fitted into a double-walled heating jacket filled with water, and the heater blower in the box with a saddle fuel tank.

Alcohol delivered from the tank, was vaporised by the 220V-operated electric fan, ignited, and blown out through a jet (blow lamp principle) into the inlet at the bottom of the heating jacket.
The alcohol feed was controlled by a thermostat, keeping temperature of the water inside the heating jacket below 40C.

The Vorwarmer was mounted on the standard one-axle 900 kg. trailer chassis. A hand-pump was fitted on top of the T-Stoff container.
Note the additional cable brum, mounted on the trailer.

An abandoned Vidalwagen (V2 Rocket Transporter) on the front, and two Vorwarmers on the back.

The question of T-Stoff freezing rarely arose since the policy was to launch the rocket asap after fueling, so the Vorwarmer was seldom used, yet remaining an important vehicle of a V2 convoy.