Hey thanks for dropping by already.Anyway, can you tell me what is the following gears for?
-Buoyancy Compensators
-Dive Computers
-Scuba Fins
-Scuba Diving Gauges
-Dive Masks
-Scuba Octopuses
-Scuba Regulators
-Scuba Tanks
-Diving Weights and Belts
-Dive Reels
-Scuba Hoods
Thnx a lot if you can answer what all these gears are for i mean the reason for it…

The majority of this gear should be used only after significant training. Your local dive shop should help you with that. It is also important that your gear be maintained — your life may literally rely on it.

-Buoyancy Compensators. This typically serves two main purposes (and maybe a third). First, it is a way to attach the tank to you. Typically a BC is a vest or includes a harness. Second, it has an air bladder that can be inflated and deflated to keep you neutrally bouyant (so you neither float nor sink when in the middle of the water column). This is needed because your bouyancy does change over the course of the dive. As the tank pressure is reduced, you become more bouyant. As you descend, your wetsuit is compressed which makes you less bouyant. Sometimes, the BC may also be used to carry the weights (called weight integrated) or have the octopus integrated into the BC inflator.
-Dive Computers: See gauges. Typically, this will include both a dive timer and depth information recorded real time. This helps avoid the bends. The air pressure can also be incorporated (but might not be).
-Scuba Fins: These greatly reduce the effort required to swim.
-Scuba Diving Gauges: These monitor four things. A compass provides directional information. A pressure gauge tells you how much air is left in your tank. A depth gauge tells you how deep you are. A bottom timer tells you how long you have been underwater. These are crucial: time and depth need to be managed to avoid the disease known as the bends. Air pressure is also crucial — without air in the tank, you have no air source.
-Dive Masks: This functions by creating a pocket of air in front of your eyes and allows you to see clearly underwater. (Note: It does not do anything to prevent pressure from being applied to the eye — they can handle the pressure).
-Scuba Octopuses. A spare second stage — see below.
-Scuba Regulators. This is what allows you to breath while underwater. The regulator has two stages — one reduces the pressure from over 1000psi to around 100psi (a bit of a fudge here) and is called the first stage. The second stage is attached to the hose and is what goes in your mouth. It reduces the pressure further and is a demand valve.
-Snorkels: This allows you to breath (while on he surface) but with your face in the water.
-Scuba Tanks: This is a metal cylinder that contains pressured air. A tank will typically hold over 3000 PSI.
-Diving Weights and Belts: The belt holds the weights to you. It is designed to be released in an emergency. The goal of the diver is to be neutrally bouyant. Because some dive equipment (wetsuit) and most people are naturally bouyant, some weight must be worn to be neutrally bouyant.
-Dive Reels: This is a specialized piece of gear that is used in a few different contexts. It can be used to mark a route underwater (most often in cave and wreck diving), or to help when setting up a search pattern. (Both caves and wrecks are hazardous environs where you cannot not ascend directly to the surface and where it is possible to be in zero viz from a silt out). It can also be used to help guide a surface float up.
-Spearguns : These are used to shoot fish (think of it as underwater hunting). Frowned on in most locations.
-Scuba Hoods: Since much of your body heat is lost through your head (and water sucks heat from the body even quicker than air), this can help keep you warm.

People snorkeling use a mask, fins and snorkel. Some also use a hood/wetsuit, weights and snorkel vest. A spear gun may be used as well. The rest of the gear is used only in diving.