AH-UV-12-L 12 watt replacement lamp / bulb. Replacement bulb for 12watt UV systems using bulb type 4 pins at one end, 265mm long, 15mm diameter only. Please note this bulb is only compatible with 12w UV systems using a 4 pin at one end type connector (please see images for example) with the following dimensions: Bulb Length: 265mm, Diameter: 15mm. This would not be compatible with any other wattage of system or bulb type (does not fit 2 pins at each end type). Lamp / Bulb life: Up to 1 year Max flow rate: up to 4 Litres Per Minute Please ensure that proper pre-filtration is used before the UV lamp to ensure the effectiveness of the UV system, the lower the water hardness, turbitiy, and flow rate, the more effective the system will function. It is recommended to use a UV pre-filter system to filter sediment from the water prior to the UV system.