Instruction: Output yes if the supporting document can answer the given question. Otherwise, output no.

Input:
Question: Do these drops expire?
Document: They both use the same amount of drops, so what's the deal?
Use this drops in Bolivia for a month straight and had good safe water without the weight of a filter.
I have used these drops previously and they worked very well. I am keeping them in my emergency prepardness kit.
these drops are amazingly small and light for packing in a bug-out bag, or using if you run out of water in an emergency situation
Keep those around in my hiking bag and BOB 72 hour bags. Never know when stranded and need clean water. Those drops work great..
Used this product for a mountain climbing. After fetching water from river and lake, used the drops. No bad chemical taste and did not kill me, although its instruction scared me a bit initially
Very easy way to make sure the water is clean and drinkable. Two easy steps (couple drops from each bottle) and then you wait a couple minutes and the water is all clean. Highly recommended.
It works. I used it, didn't get sick, water tasted fine. Kind of gives a slight chlorine kind of taste, but works great. I'll be sticking with the drops over tablets now.
A drink of the gods. These Drops allow you to drink 30G of water, SAFE water...without using a filter (yes, filters add weight...especially if you're traveling UL)
When you get tired of digging into a pack and getting a pump going while hunched over a shoreline and then repacking the pump and then cleaning the filter and then changing the prefilter - try the drops. Keep it simple. Keep it light.
Answer: yes