Control multiple flash units with ease using the Yongnuo YN-622C-TX Flash Controller for Canon. The controller slides into the hot shoe mount and makes use of a 2.4GHz frequency that offers a triggering range of 328 feet. It offers TTL, manual, and multi flash modes to give complete freedom in setting up the scene. The YN-622C-TX uses an LCD screen to display settings and make adjustments. It even includes an autofocus assist beam to aid in low-light environments. The controller also features a built-in mini-USB port that can be used to receive firmware updates. It is compatible with Canon E-TTL / E-TTL II cameras.