'Standard' SCUBA equipment is different for each diver but if we only look at a recreational diver going to less than 30m then he would have :-

1. A Bouyancy Compensator (BC). This is an inflatable jacket that holds the air cylinder and allows you to adjust your bouyancy so that you remain neautrally bouyant.

2. A regulator. This is the bit you breath from. It connects to the air cylinder and reduces the high pressure to a pressure you can breath.

3. A weight belt. Wearing a wet or dry suit makes you bouyant so a weight belt compensates for this.

4. Mask, Fins and a Snorkel. So you can move around and see things!

5. An air cylinder. A steel or aluminium cylinder to keep compressed air in so that you can breath while under water.