The vendor shall provide scheduled maintenance services, unscheduled repair (corrective) services and other on-site and off-site services (Topeka, KS) to keep the Waters instruments performing in accordance with the operating specifications set forth in the applicable Waters documentation. 4.3.1. Scheduled Maintenance: At least one (1) preventative maintenance (PM) visit per year per system must be included in the agreement, which must include replacement of all parts subject to wear as defined in the product specific PM checklists, labor, and travel required for the PM and repair of non-functioning instrumentation. This will include the supply (and installation if not customer installable) of maintenance parts as required. The parts shall be guaranteed Waters Quality Parts. Preventative maintenance will be provided at a mutually agreed upon time, during which the appropriate parts and supplies will be replaced. Check installed firmware versions and update as necessary during the performance maintenance visit. 4.3.2. Unscheduled Repairs: The vendor shall provide other maintenance or repair services where required, as well as any additional repair and maintenance services required for the listed instruments. This must include labor, travel and repair of non-functioning instrumentation. This will include the supply (and installation if not customer installable) of maintenance parts as required. The parts shall be guaranteed Waters Quality Parts.