The Canon Speedlite Transmitter ST-E3-RT (Ver.2) is a radio remote flash trigger that sits in your camera's hot shoe and controls compatible Canon Speedlite flashes wirelessly. It can fire up to 15 compatible radio Speedlites over distances of up to 30 metres, without needing line of sight. This updated version enables the wireless radio features of the Speedlite EL-1, including wireless second-curtain sync, very low power output down to 1/8192 and Flash Exposure memory. It also works with the Speedlite 600EX II-RT, 600EX-RT and 430EX III-RT and a wide range of EOS DSLR and mirrorless bodies, such as the EOS R5, R6, R7, R10, R50 and 5D Mark IV. A large backlit display and dedicated buttons make group and ratio settings quick to change. After comparing online prices, www.marvel.co.za should be the cheapest on this product.