by halhiker » Tue Oct 15, 2013 10:52 pm
Two liter soda bottles. They're pretty tough, they don't leak and they weigh less than 2 oz. I've also used 3 liter soda bottles as well. (I like those because the opening is a bit largers) Also, I don't feel like I've left something behind if I decide to cache a couple. Gallon Gatorade Bottles aren't bad, either although they are a bit heavier.