The MSR Guardian Military-Grade Water Purifier Annual Maintenance Kit contains all the necessary components and instructions required to maintain the MSR Guardian Purifier's performance and reliability; packed in a small, convenient carry case for field use. Kit includes: Instructions, Pressure Relief Valve Assembly, O-Rings, Cup Seal, Piston, Umbrella Valve, Silicone Lubricant and a Cleanside Cover. Manufacturer's limited 3-year warranty. Made In USA.