If you are searching for a first aid kit you will find there are millions of search results found on the web. The key to selecting a first aid kit or emergency kit is to determine what you are specifically preparing for what tools or supplies you have training for and are capable of using. If you work construction for instance and need first aid supplies you are going to want something that is portable and has the contents to treat the inuries you are mostly likely to see. I have seen many places order a huge trauma bag with lots of items and tools that nobody on the sight is capable of evening operating and if they did it could be done improperly and cause more damage than good, so it is always a good idea to only buy what you are trained for and save the extra money.
When determining what emergency kits you need, look at what disaster you are preparing for and where it will be used. If your going to be out in the wilderness you are going to want something that will treat various injuries and the elemental effects but yet be light weight and portable if you will be mobile. If your loking at an emergency kit for your home, you need to consider what you preparing for and what type of climate you will be in, what medical emergencies might arise, do you have the tools to shut off the gas lines in case of a rupture, and lighting not only for conveience but to alert others of your where abouts if you need to.