The Westcott FJ400 II is a 400W flash unit for professional photography that can be powered by both AC and DC, making it versatile for studio and outdoor use. It features a short recharge time that supports continuous shooting and comes with a replaceable FJ Pro battery, allowing for longer operating time with more full-power flashes per charge compared to similar models. The flash unit is equipped with an intuitive OLED touchscreen for easy parameter adjustments, offers built-in help screens for user guidance, and maintains a consistent color temperature across a 9-stop power range. A key innovation is the Creative Mask function, which allows photographers to program up to six different light sequences without moving the lights, making it ideal for layered compositions and dynamic effects. With a compact, lightweight design in black, it combines portability with robust performance. This flash unit is compatible with FJ Pro batteries used in FJ800 and FJ400 II models, enhancing its adaptability for various photographic needs. Built for durability, it meets the demands of application-based reliability and focuses on dependable operation and practical benefits for photographers seeking precise light control.