There are a bunch of extras that can make your time diving easier or more productive and here we will discuss a few of the main ones.
For an increasing number of spearos, a freedive watch is becoming one of their main safety devices. I doubt there's a diver around who isn't interested in how deep they're diving and for how long but this is just the start of what a watch can do for you. One of the main functions of the watch is to accurately keep track of your surface intervals. Cutting your time short on the surface is one of the main contributors to shallow water black out and the fact is most divers simply cannot accurately tell when it is safe to dive again.
Here are the main features to look for:
Current depth and dive time
Depth and time of previous dive
Surface interval time
There are plenty of other functions found on most watches but these are the 'must haves'. Another thing to look for is a user changeable battery.
A good dive light is a big help hunting under rocks and looking for crays as well as diving at night. For spearfishing you want a relatively small light. They can come with either a halogen or LED bulb. Nowadays the LEDs beat halogens hands down. The LED is generally much brighter with a whiter light and no dark spot in the middle but their main advantage is efficiency. Between the two otherwise similar Princeton Tec lights we sell in halogen and LED versions the LED has more than twice the light output and 10 x the battery life. You don't need to be an accountant to figure out that it isn't going to take many battery changes to make the LED the more economical choice. Speaking of output, lights should be rated in lumens. This is a far more objective rating than candlepower which can be cheated by being measured different ways.
Like anything electrical your dive light must stay dry. Most lights use o-ring seals to achieve this and the less openings for water to enter the better. Smaller, cheaper lights generally have twist on/off head which is not as safe as a switch. A magnetic reed-switch is best but beyond the scope of most little spearo lights.
A good gear bag is a vital piece of equipment for carting your kit around and keeping it safe. Very few bags other than specialist spearfishing gear bags will be long enough to store your freediving fins and virtually no scuba style bags will be. With gear bags durability is the main feature. The zips must be big, chunky, rust free and preferably have YKK written on them.
Vinyl is the most popular material for bags as it is durable and easy to clean - bear in mind that most spearos' dive bags get used regularly as a fish bin so ease of cleaning is a must [although after spending countless hours in cramped cars with dive bags I'm not convinced many of them actually are getting cleaned].
Vinyl is totally waterproof as well so most bags will remain relatively watertight although they will eventually leak through the seams.
It is often the handles getting torn off that retires your gear bag. This usually happens when someone only grabs one side and pulls. If your bag is pretty heavy and whenever rough handling is likely, like when travelling by air, tie the handles together so whoever grabs it is forced to use both handles. The handle should be made of a continuous piece of webbing for maximum strength and minimum stress on stitching.
Gun bags aren't hugely popular unless you're travelling by air. I guess most spearguns are tough enough not to need any extra protection during standard use and the bag is just extra, unnecessary bulk. If you do use a gun bag be sure not to store your guns in there wet as this is the fastest way to rust out your spears.
As always with spearfishing less is more when it comes to catch bags. The most popular are simple mesh bags that can be tied to the back of your float and add virtually no drag until you start filling them up and who's complaining then?
For crayfish simple snares are usually better than a bag as they offer even less drag than even the slimmest mesh bag. Made of a bit of nylon and some crimps they clip onto the back of your float and its like they're not there until you start loading them up.
If you are after shellfish a waist catch bag is a great bit of kit. These bags clip around your waist like an apron and mean you can get both hands going. They can get a bit heavy as you fill them up though so you need to be careful how much weight you attach to yourself.