There are two basic types of speargun - pneumatic and sling
The pneumatic speargun contains an air chamber, which, when pressurised, allows the spear to be fired using air pressure.
Some advantages to using this type of speargun are:
The bungy type of speargun has one or more rubbers which the user stretches by hand and locks on to the spear. The user then pulls a trigger which releases the spear using the rubbers elasticity to fire it through the water. Some advantages to using this type of speargun are:
The line on the rubbers is the highest wearing part on this type of speargun, and is very cheap to replace - most fishing stores sell this line. Next, the rubbers themselves also wear out and lose their elasticity – these are also fairly cheap and very simple to install. Storing rubbers in the fridge will also extend their life. JBL make an excellent range of bungy spearguns more...
The majority of the servicing of this type of speargun can be done by yourself. Having a simpler design also means a longer life with lower maintenance cost. As for the best size - a 110 is good for starting out...catch smaller reef fish and some of the larger species with this speargun. I recommend and use this type of speargun.