Interfit INT491 EXD400 Twin Head Softbox Umbrella Kit Description. The new Interfit EXD400 combines all the features of the multiple award wining EX150 MKII with fan cooling & a larger polycarbonate body. Easy to use controls make the EXD400 desirable where finite control is required over the output settings along with double the power of the EXD200. Versatility is a buzz word often used to describe a studio strobe here its certainly is the case in this compact 400 watt head. Each head features user changeable flash tubes switchable modelling lamps fan cooling for prolonged use & Infrared & white light sensitive light sensors & a additional easy to use rear handle allows for precise positioning. The EXD400 also features a pre set flash function to enable the head to reduce the pre focus flashes bysome of todays Digital compact cameras enabling the Sync cell to correctly pick up the first second orthird flash therefore ignoring the pre-flash used for focusing.