HHO kit has different devices and components. All together they are HHO Kit. This HHO system usually has components like dry or wet hho cell. HHO reservoir for the electrolyte of the system. HHO bubbler, pulse width modulator (PWM), wires, hoses, electrical connectors, hose clamps, inlet connector for the HHO gas.

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Dry HHO cell is the generator, which is producing HHO gas. The dry cell is actually not dry inside, of course, it consists of liquid inside. This liquid, the electrolyte actually comes from the reservoir above only by the gravity way. The configuration and design that electric current it passes exactly through the plates are important. There is no way that electrolytes will be going near the SS plates. The Dry HHO cell looks like that:

Wet HHO cell is practically smaller plates and working surface and they stay in a common bath of electrolyte. In this case, it does not need a reservoir, because the whole design is 2 in 1 electrolyzer and the reservoir. The electric current passes through the SS plates and through the electrolyte as well, practically most of the electrons pass near the plates because they looking for the easier way to get to the negative plate. That’s why the wet cell is not much efficient like the Dry HHO cell. Gas production is smaller than the Dry cell by using the same amount of energy. The wet cell is like the 1^st generation of the electrolyzers.
The wet cell looks like that:

HHO reservoir is usually used with dry cell and it stays above it. So, by the gravity way, it fills the dry cell with electrolyte. Practically during operation, one hose which comes from the bottom of the reservoir is filling the bottom of the dry cell with electrolyte and another hose from the top of the dry cell is pushing back to the reservoir produced gas and some part of the electrolyte. This way the electrolyte is circulating between the dry cell and reservoir by itself. There is no need for a pump. You can see that here in this video:
The HHO gas is separated from the electrolyte in the reservoir. The gas I lighter and goes above the liquid, so the reservoir must have a gas connector and hose on the top of the reservoir, which is delivering the HHO gas to the bubbler.

HHO bubbler is the device, where the gas is bubbling before goes to the air intake of your engine. The bubbler has 4 functions:
1. Collecting the rough steam of the produced gas.
2. Drying the produced gas.
3. Acting as a back-fire device (spark arrestor). Installing in a carburetor engine may cause spark back. Other engines (petrol injection and diesel, turbo-diesel, and Common rail) there is no chance of back spark.
4. Preventing some drops or even liquid goes to the engine intake.
In the bubbler usually has some water, so the produced gas is able to bubble there, but if it’s not, this is not a problem, because the HHO gas is lighter than the air and it goes higher. In addition, the vacuum created by the engine will such the total amount of gas to the intakes and respectively to the cylinders.

HHO PWM is the device, which controls the electrolysis process in the HHO generator. Most PWM’s control the voltage, load and some models also the frequency. There are many models on the market, some of them are just variable motor controllers used for this purpose, they operate at 12V or 24V for different charging systems. Light vehicles usually have 12-14.4V DC charging systems and trucks/buses and other bigger engines operating at 24-29V DC.
The role of the PWM is to limit the amps you are putting as a load on the vehicle’s battery and alternator and the whole charging system. For this reason, the PWM protecting the car charging system of too much load on it.

The relay can be used in electrical schemes where the PWM has no integrated such. Remember that all relays have only one function to start and stop something, they do not do other tasks. Never override the relay with more than 75% of its capacity, for example, if the relay is 40A, your maximum load must be 30A.

Fuse for 20, 30 or 40 Amps is a must in the HHO kit, cause this means security and protection of starting a fire in your vehicle, for example, if you load some tiny wire too much. Make sure you use quality fuse for your vehicle’s system and most important to be for exact load protection. For instance, if you use normally a load of 20A, your fuse must be 25A, so in case something happens to the PWM and the amps exceed 25A, the fuse will trip off and protect overloading.

The rest of the items you may need is the exact section of the wires for a certain load, good quality connectors for hoses and wires, if you use buttons, fuses, fans, pumps and so on additional devices are good to mount properly and protect all of them during the installation.
Above mentioned devices, you can buy here as an HHO kit ready for installation or one by one! But as a kit, it will be cheaper price and also you will be sure that everything fits properly, cause we have tested all of them many times and we have done hundreds of installations by ourselves, so we could see all negative aspects and hard moments during installation! The idea was to prepare everything to be very easy for you!