Start Base Wax: The purpose of a base wax is to adhere the kicking wax to the kick zone of your skis. What makes Start base waxes unique is their use of klister as a solution for maintaining durability.
Start base waxes are comprised of a combination of synthetic rubber, klister, and pine tar. The difference between base wax and base wax extra is that base wax extra contains more klister which will improve durability in coarse grained snow. Which base wax you will use is dependent on the conditions you are skiing in. In fresh snow and moderate snow conditions, regular base wax applied with an iron is reccomended. For artifiical, transformed, coarse, or abrasive snow, base wax extra would be reccomended.
Application: Start Base wax is to be applied with an iron that is only used for kick waxing. You can rub the iron on the kick wax to warm it up, and then rub the warmed can onto the ski in a thin layer. Iron into a thin, even layer, and allow to cool. This stuff can be tricky to apply, but it is 100% worth it.