Building a first aid kit

I work in the construction industry, often in remote sites, and it amazes me that most guys on the job have next to nothing for serious first aid. 2 weeks ago I cut myself with a chisel and without my first aid kit I would have been in trouble pretty quick. Yesterday a guy fell about 10' off of some scaffold and smashed his face into the rocks. I got my kit and administered first aid, picked up his teeth and drove him 35 min. to an urgent care clinic.

I am looking for a good source of first aid supplies to add/replenish my kit. I am not looking for Hello Kitty band aids and Bactine, but looking for gauze, trauma pads first aid for burns, instant ice packs etc.

Also, does anyone have experience with Celox granules? http://www.celoxmedical.com/eur/eurp...celoxgranules/

Thanks and be safe.