ELECTRICAL EQUIPMENT AND SUPPLIES (EXCEPT CABLES AND WIRES),, ENERGY CONSERVATION MATERIALS, CONTROL DEVICES, AND SYSTEMS, PLUMBING EQUIPMENT, FIXTURES AND SUPPLIES, SWIMMING POOL EQUIPMENT AND SUPPLIES (EXCEPT CHEMICALS), CONTRACTUAL MAINTENANCE SERVICES: HEATING UNITS, VENTILATING EQUIPMENT, ETC., CONTRACTUAL MAINTENANCE SERVICES: PLUMBING EQUIPMENT