First Aid Kits are FSA Eligible because its primary use is to give first aid medical treatment. The contents of First Aid Kits varies depending on the experience and knowledge of the one who organizes and keeps it. Example, for this specific First Aid Kit, this is used on emergencies during extreme weather, you can tell by the description that this kit has a weatherproof case.
Fact: Did you know that first aid kit were created just because of a fateful conversation thus gave way to the creation of Johnson & Johnson's First Aid Kit, which was released in 1888.