The All Pond Solutions CUV-118 18w UV Light Steriliser is designed for ponds and aquariums. Unlike other sterilisers, this unit has three inlet/outlets, making it versatile for various setups like dual-fall waterfalls or a waterfall and a filter. It includes three stepped hosetails to accommodate different hose sizes and a separate glass viewport that can replace a hosetail for a one-in/one-out configuration. This model features an external ballast.