An emergency bag does not help by itself! Up-to-date training is essential. If possible, several people in the group should be able to help and several first aid kits should be available. Because if the only trained helper with equipment is buried or injured - the others are left looking pretty "stupid".
It is not advisable to buy pre-packed first aid kits without personal supplements. The material in these "standard sets" is often not put together according to medical criteria - as cheap and as filling as possible. This does not help much in an emergency. Why not put together your own bag with the following materials? Another option is to buy specially coordinated sets.