First aid satchels or boxes

These should contain at least the items required by MSN 1726 for the ‘first aid kit’. One should be kept close to the ship’s medical store for swift transfer to the site of an accident. If you have more than one, the other(s) should be placed away from the medical store so that if the store is destroyed by fire you have an easily reached first aid kit. These kits should be checked frequently and re-stocked as required.

Most store bought first aid kits, especially the cheap ones, are very poor in terms of quality, quantity, and selection of items, and are only suited for treating very minor injuries. A homemade kit, if properly prepared, is generally better and sometimes cheaper than most commercial kits.
A generic first aid kit is better than nothing. However, the contents of a first aid kit should be optimized for local conditions. For example, a kit for hikers in snake country should have a snakebite kit. A kit aboard a boat should have medications for seasickness.
 
One list of items for a first aid kit are as follows:

Adhesive bandages are one of the most commonly used items in a first aid kit
* Dressings (sterile, applied directly to wound)
o Pads
+ Sterile eye pads
+ Sterile gauze pads
+ Sterile nonadherent pads
+ Burn dressing (sterile pad soaked in a cooling gel)
* Bandages (sterility is not necessary, used to secure a dressing)
o Gauze Roller bandages - absorbent, breathable, and often elastic
o Elastic bandages - used for sprains, and pressure bandages
o Adhesive, elastic roller bandages - Very effective pressure bandages or durable, waterproof bandaging
o Triangular bandages - used as slings, tourniquets, to tie splints, and many other uses

Sometimes dressings and bandages are combined, in which case they must be sterile.