If you are a novice to survival gear, then you need to understand that the bigger and flashy knives are not the best type you can choose
. Often these extra features can weaken the knife lowering your chances of surviving successfully. Blades that have a saw one side often do not work as well as purchasing a separate saw for your kit. You should also stay away from knives they give you any sort of gimmick, such as hollow handles for storage, since these often can we can the integrity of the blade.
This does include the length of the blade. You should buy one that is not too large or long so that you can get the most use out to this while on the field.
Some of the best knives you can get are called Tang knives. These are constructed in such a way that one piece of metal makes up the handle and the knife itself. They handle may be coated with another material for ease of use and to make the grip more comfortable. You should always make sure that your knife and handle is constructed in one piece, since when they are separate this can become a weak point on the knife.
Tang knives come in two styles. Wide tang has the blade and the handle roughly equal size. A narrow tang becomes thinner at the base of the blade extending to handle. Often narrow tangs are inserted into another grip.
You should also take in the blade type when you purchase your knife. A serrated blade is one of the best for sawing and administering first aid and for self defense, but the major drawback to this is that you cannot sharpen it while you're out on the field. A smooth blade may not perform these functions as well, but it is the best all around usable type that you can purchase. You can sharpen these with a rock is the merchants your rises, which the serrated blade needs special equipment.
You should always buy the best knife that you can afford. You will be relying on this heavily when you're out of field, and if you have a substandard knife it can often make the difference between life and death.
Survival knives are the most important part of your survival gear at any time. By getting a quality knife you can use this on the field for many years making surviving easier.