This MSR Miniworks EX water purifier system with ceramic filter has only been used on very few occasions, probably less than 40 liters has gone through this filter in the last 4-5 years. The filter was always rinsed and fully dried before long term storage. It filters well when filter is freshly cleaned, but requires frequent filter cleaning to remain efficient. The pump action is much better than other pump filters I've owned. I'm switching to gravity filtration, and will not be using this anymore, I'm done pumping. Brand new it was $100. Asking $65 with shipping included. If you're local (NE Minneapolis) and want to pick it up $50 cash in hand will do. Please respond via email: ash.pottery@gmail.com