Don't think they mention this very important detail in their ad - it's THREADED!! It works but you will certainly not be putting it on and off in a hurry as is often requires by photographers. Threads onto the end of your filter as opposed to the quick twist style. Disappointing.
Works not bad but watch how far you push the card into your hot shoe (this may also involve some trimming) as the camera may detect it as a device and cause your camera to not let you use your pop up flash because it thinks you have attached an external flash. Great for travel in that it takes up almost no room in your bag.