I had this on my night vision, the threads are marked 52, and the reducer is marked 52 -> 46, I assume its mm. I believe SLR's and DSLR's have many differing sizes, depending on brand. You may want to look up your specific camera's lens size, and bid accordingly.
again, like I'[ve posted, it's threaded, with 52 (mm?) and a reducer that takes it down to a 46 (mm?) thread...there are FAR too many brands and types of cameras out there for me to know the answer to this question. I have posted that I had it on my night-vision, other than that, all the information is in the description. Sorry I can't tell you more about your camera.