NGB250 250W & NGB425 425W Switching Power Supplies SL Power NGB250 and NGB425 Switching Power Supplies are single-output devices that meet medical and industrial safety standards. SL Power NGB250 provides output power of up to 250W with airflow, only derating to 180W convection-cooled, while NGB425 provides up to 425W with airflow, only derating to 300W convection-cooled. These power supplies meet Class B emissions levels and feature a universal 85VAC to 264VAC input range and less than 100µA leakage current.