Flash Range: 40-35,000 RPM/FPM. A truly portable unit, the DT-315AEB operates independent of line power via an exterior battery pack that can be carried with a convenient shoulder harness or set down to allow the operator full movement for visual inspection. When fully charged, rechargeable batteries power the strobe for approximately four continuous hours. The DT-315AEB also incorporates the same impressive features as our DT-311A and DT-315A strobes.