A fully-featured unit powered by a lithium-ion battery, the Modus 600RT TTL Speedlight from hahnel is a capable flash offering both E-TTL / E-TTL II metering for Canon cameras as well as a manual exposure mode. It boasts a powerful guide number of 197' at ISO 100 and 200mm but does not compromise on speed, with blazing fast recycle times of 1.5 seconds or lower. Another key feature of this flash is its built-in 2.4 GHz transceiver, which allows you to easily sync it with other compatible flashes or wireless remotes at distances of up to 328'.