These Tubular Flasks are great for carrying all sorts of stuff for both urban & wilderness survival, camping, hiking, etc. They can hold 2 oz. of liquid, as well as assorted small items. The caps have a seal when you first put them on, so if you use the flask for something like medical supplies, you will know if the seal has been broken. The cap is still reusable after the seal has been broken. We have used them for small kits, as well as carrying liquids such as maple syrup when camping. They measure 5-3/4" long x 1-1/8" O.D. x 13/16" I.D. They are sold in packs of three.