The Department of Water and Environmental Regulation (DWER; the Contract Authority; the Customer) requires the provision of ad-hoc water quality multi-parameter probes, sensors and associated accessories to support its responsibilities for measuring water quality in inland waters, marine waters and estuary water. DWER operates and maintains a large instrument inventory for which it needs replacement parts and servicing, and will procure replacement instruments of the same brands, YSI and EUREKA, to ensure operational continuity, user familiarity and backward compatibility.