A technically advanced flashgun powered by an interchangeable lithium ion battery pack rather than all too short lived aa batteries the tli is jammed full of features and boasts a 15 second full power recycle time with a guide number of 58 designed to integrate seamlessly with canon e ttl systems flash exposure bracketing flash exposure compensation and flash exposure lock the tli c is also fully compatible with the canon 600ex rt and 580ex ii as master or slave flash in addition to t