The four models offer a wide range of standard features that includes discrete continuously variable power adjustments over a full 6 f-stop range. StudioMax III accepts all the Photogenic Quick-Change light shaping accessories. These accessory options include barndoors, grids, snoots, scrims, diffusers, soft boxes and umbrellas. These lights are easy to carry for location work, weighing from 2.4 pounds to 3 pounds, so make them your travel lights or hair and accent lights in the studio. Now Built-in Radio Triggering for StudioMax III Optional built-in radio triggering is now available for all new StudioMax III AC and AC/DC monolights. The all new four channel RTR receiver is built into the monolight and is triggered by the RTT radio transmitter (sold separately). The wireless triggering range is 150 feet. The antenna is inside the flash unit to prevent breakage.