Replacement 12w bulb/lamp will fit 

MODEL NUMBER: LUXE-UV-12W

This 12 Watt energy efficient Ultra-Violet  lamp used in water disinfection units to aid with the deactivation of bacteria, viruses and other micro-organisms. Common applications are disinfection of drinking water.

A UV Lamp is the heart of the UV treatment system. The lamp needs to operate correctly to ensure the water in your home is safe. 

Unlike regular light bulbs, UV Lamps do not burn out – they solarize. This means that over time they reduce in their light wave intensity to about 60% of what a new UV lamp provides. This point is reached usually after one year, or 9000 hours, of continuous use. 

It is EXTREMELY IMPORTANT to replace the lamp every year as part of your maintenance schedule. Almost all UV systems are meant to operate continuously, you can actually significantly shorten the life of the bulb by turning it on and off.