This item is incorrectly filed under 'Digital Camera Battery': The 'Canon Speedlite Transmitter ST-E2' is an infrared remote transmitter for controlling & triggering one or more compatible off-camera Canon Speedlite flashgun wirelessly: It should be filed under 'Canon', 'Flashguns', 'Accessories'. The filing system under 'Canon' should not make a distinction between 'Digital Camera Flash' & 'Film Camera Flash' since the use of flash lighting is completely independant of the medium used for recording the image (film or digital sensor) & Canon Speedlite flashguns & accessoriesare equally suited to either medium. The same applies to the 'Digital camera lens' & 'Film Camera Lens' categories which should also be amalgamated (or renamed to reflect the EF-S / EF lens distinction to distinguish between those lenses that will only work with camera bodies equipped with APS-C-sized sensors & those lenses that will work with all bodies.