I bought a Monoprice (knock off Pelican) hard case for less than $20 because my Xterra didn't come with the first aid kit and people want a lot of money for OEM ones on eBay. I had to extend the straps but it works fine for less money if you are on a budget.
I have to strap my straps in an X to keep the case from sliding out since it is a little small. I have been thinking maybe a strip of velcro would keep it from moving enough to not be an issue
I've not opened my bag in years.
This post has alerted me to check for any expired items which may be inside of it.
Along with what came from the factory, I included some otc meds such as Benadryl, Tylenol, Aspirin etc etc etc.