Cody Morganwrote a review of MSR MiniWorks/WaterWorks Maintenance Kit on August 8, 2015
Familiarity: I've used it once or twice and have initial impressions
After using my Miniworks filter for over 5 years the only part that needs to be replaced is the umbrella valve. As others have mentioned, it really seems the umbrella valve should be included in this kit, but it isn't. I found replacement umbrella valves at casanovasadventures.com. 3 pack for $6.