Regulators

 

Believe it or not there is a large difference in the "feel" and performance between regs. "Regs" are made up of three parts; a first stage (attaches to the tank), primary (that you put in your mouth) and alternate (ocy / spare).

Be aware of buying second hand and goods online, your regs are your life source underwater, all equipment must be serviced every year. The advances in engineering over the last few year’s make older secondhand equipment obsolete  by comparison.