I'm selling this because it's oversized for solo trekking with a 10L capacity. It's a new, unused item, but please understand that it has been handled by someone else, so only purchase if you are comfortable with that. Suggested retail price: 19,800 yen *Excerpt from the HP below* This is a gravity-fed, automatic water purification system that requires no pumping. It can purify 10L of water at once, making it ideal for large groups or base camp use. The hollow fiber membrane filter has a purification capacity of 1.75L per minute and can be easily cleaned by backflushing (reversing the water flow). A universal bottle adapter is included that fits large-diameter reservoirs like Dromedary bags, as well as small-diameter Platypus bottles, allowing for efficient access to clean water. *Quoted from the official Mochizuki HP*