"Use this small lighting kit in a variety of ways. As copy lights, this kit excels! With the 55 degree beam angle and guide number of 72, two lights can handle almost any size copy project. These lights can be used with digital still cameras, film cameras and video cameras. In the studio, create special lighting effects on backgrounds, as hair lights or even colored fill lights in portraiture. The 5500-6000k color temperature will match any studio system. The S-25M strobes can be fired 3 ways, by synch cord, by built in slave or by the test button for pre-visualization|Guide Number: 72 at 10ft with ISO 100|Color Temperature: 5500k - 6000k|Fireing Modes: Synch Cord, Built in Slave, Test Button|Size: 3"" diameter x 5 1/2"" long|Weight: 6 ounces|Watt Second Output: 25 watt seconds each light|Slave Sensitivity: About 35 ft. Depending on Primary Strobe Output"