Guide No.: 27 (ISO100 in meter); Flash covering range: 0.6m~20m (Depending on the ISO sensitivity, differs with lens aperture angles of flash head); Flash mode: M (Manual) / MUIT (Strobe); Slave: S1 / S2; Reflective flash ability: The flash head can be upward 90-degree and have 0 / 60 / 75 / 90-degree stop positions; Effective flash range: 0.7~19.3m (Quick flash: 0.7~11.1m)