The principle of the lifejacket is to inflate automatically according to the action of the water (fully automatic inflatable lifejacket), or by pulling the cable on the inflatable valve by hand (manual inflatable lifejacket).

It will be inflated within 5 seconds to produce 8-15 kg of buoyancy, which will lift the body upwards, so that the head and shoulders of the inadvertent fallen person will be exposed to the water, and will be safely protected in time.

There are buoyant material-filled life jackets, which are made of nylon or neoprene fabric and filled with buoyant material in the middle.

There are also inflatable life jackets: made from strong, waterproof materials, similar to the principle of an inflatable life buoy or swimming ring. They are available in automatic or passive inflatable versions. However, this type of lifejacket should be careful to avoid sharp objects poking through or abrading the waterproof layer, which can have serious consequences when air leaks.

Life vests should be as brightly coloured as possible, such as red and yellow, because they make it easier for rescuers to spot you if the wearer accidentally falls into the water. Secondly, life jackets generally have a protective effect on your body to keep you out of harm's way.

When wearing a lifejacket in the water, the buoyancy of the front and back pieces of the lifejacket should be in the correct proportion, generally the front piece must be more buoyant than the back piece and should allow the wearer to remain upright or lean back slightly to ensure that the mouth is exposed to the water and that there is no tendency to submerge the wearer's face in the water.

Life jackets are a guarantee of life and generally need to be kept with care.

1. Life jackets should not be machine washed or dry cleaned, nor should they be bleached or tumble dried in a washing machine.

2. When cleaning lifejackets it is recommended that a neutral detergent is used and that they are wiped with a damp towel, not soaked in water or washed with a more aggressive detergent.

3. Life jackets should be stored in the shade to avoid accelerated ageing and reduced life expectancy due to exposure to sunlight. Attention should also be paid to keeping them dry and clean to prevent them from becoming mouldy and affecting their use.