Hamburg  - Snorkelling is a wonderful and enjoyable hobby - just dive into the water and you're in another world.

But as soon as the air supply is gone, it quickly becomes obvious that you need a diving permit if you want to get a good look at life beneath the waves.

You will also need the right equipment. A mask, snorkel and flippers are part of the basic gear to go under water.

The most important item is the mask which can cost between 25 euros (39 dollars) and 100 euros (158 dollars).

It's important that the mask fits the shape of the face and creates a waterproof space around the nose and eyes without pinching the skin.

The mask should also cover the nose in such a way that you can clench it between your thumb and forefinger to equalise ear pressure as you descend.

You realise how important a good mask is as soon as you buy the wrong one: water continually leaks inside an ill-fitting mask and after each dive you have a dark pressure ring around your eyes and nose.

"No one should buy a mask without trying it on and going for a test dive," advises Stuart Acklam, diving instructor and manager of Hamburg's "Seven Ocean" scuba diving school.

If you wear spectacles or contact lenses, you should get a mask that allows you to insert corrective lenses.

The snorkel is an uncomplicated construction consisting of a bent tube and a mouth-piece made of silicon.

Very simple snorkels cost about 6 euros, better quality snorkels are available for 30 euros.

"The snorkel should have a valve at the bottom that makes it easier to blow out water when you emerge on the surface," says diving instructor Marco Mueller.

It's also possible to make mistakes when getting flippers.

Acklam points out that "A lot of people make the same error when buying flippers."

Snorkelling flippers can only be worn on bare feet and for that reason are only suitable for use in a training pool or in warm tropical seas.

But even in tropical waters Acklam believes divers are better off wearing what are known as free diving or paddle flippers.

These flippers are worn together with shoes made of neoprene.

"Neoprene shoes protect your feet against the reef and sharp corals," he points out.

Another aspect to consider is your fitness level: hard flippers are suited to good swimmers with experience and muscle mass.

But hard flippers can put a strain on your ankles and leg muscles.

If the flipper is too hard, and the force of your kick too strong, you can quickly develop a cramp.

Flippers costs between 40 and 200 euros. Neoprene shoes are on the market for about 30 euros.

That's all you the equipment you need to buy as a beginner snorkeller or diver.

"Novice divers can rent the rest of the equipment from a diving school or dive centre," says Theo Konken, head instructor at the German Association of Recreational Divers (Verband Deutscher Sporttaucher).

It's critically important that the technical part of your equipment is properly cared for and regularly maintained.

Technical equipment consists of the air regulator, compressed air tank, diving computer, buoyancy jacket, depth metre and underwater torch.

Konken advises his pupils to ensure that standards are being observed every time you visit a dive centre.

"A well cared for centre is usually a good diving centre," says Konken. (dpa)