I got myself a 4.5" X 4.5" Lock and Lock container for when I need my FAK to be waterproof.

Its just a basic FAK:
1 pair of tweezers (removing splinters, etc.)
2 packs of 10 pcs of 7.5 x 7.5cm sterile gauze pads (cover wounds)
1 Triangular bandage (many many uses)
8 Band Aids (cover little boo boos)
1 tube antiseptic cream (use with gauze)
2 Alcohol wipes (clean the wound)
2 Safety pins (use with bandage)
Personal info written on duct tape stuck to inside of box

The place I bought mine had small little circular Lock & Lock containers that looked like cat food cans! How cool is that?