Are you naturally buoyant? Are you relaxed in the water? Will you be diving with a wet suit? Are you going deep or cold?
Always consider your plan as a scuba diver when selecting gear. What type of diving will you be doing?
Proper weighting will make you a much more efficient diver. Are you naturally buoyant? Can you take a light breath and float effortlessly in a pool? Do you sink and need to tread water?
