The Rinnai INFINITY A-Series and EF-Series are continuous flow hot water systems for residential applications. These water heaters produce endless hot water, and unlike electric cylinders, are energy efficient as they are only on when you need hot water.
There are five models to choose from in the A-Series depending on your hot water needs. Model numbers represent hot water capacity, for example the A16 produces 16 litres of hot water per minute at a 25 ° Celsius rise.
There is one option in the EF-Series which is an external gas condensing continuous flow hot water heater making this more efficient as it uses waste heat from combustion to pre-heat the cold water coming in. 
All Infinities come with inbuilt frost protection and electronic ignition (electrical supply required).

Options available are Pipe Cover, Sideways Flue Diverter, Security Bracket, Metal Recess Box, Compact Controller, Bathroom Deluxe Controller and Kitchen Deluxe Controller.

Infinity A16 (and other Infinities) specs at a glance

Warranty

Installation Guide

Operations Guide