Because of market competition, you won't go wrong most of the time if you go by price as a guide to quality when buying tools. If you're pondering whether to buy the $100 or $200 tool, go with the more expensive. Quality tools are a joy to work with and, properly adjusted, they will produce superior results. Also, it's less expensive to buy a quality tool the first time than to replace a lesser tool with a better one later on.
Insects love warm electrical components and air conditioners are full of them. If you want to keep insects out, experts say do not use insecticides, because the electrical components will not like them. One option is to get a special cover for your relay switch, but be aware that it has to be installed by an air conditioning technician. The cheapest (and easiest) way to keep them away is to use a flea collar. To install the flea collar, shut the power off to the air conditioner and simply placed the collar near the relay switch.