Works well with Jinbei EF-150. Helps control light scatter. Appreciate the extra gels, although I wish there was a way to stack the gels, but the magnets aren't strong enough to hold more than one gel at a time. Fit and Finish: Looks solid enough but not overly so. The front element slider works well for the moment, but it seems like it could loosen over time with heavy use. It's made of hard plastic and doesn't offer much assurance that it'll take a hit if it ever falls down. The time will show. I notice that the front element on the attachment that I received was missing a screw. This doesn't appear to affect performance, but it should be noted that this is in line with quality control standards. Function: Narrows the light beam to a much smaller spread and helps a lot with light scattering. I'm wondering if the spout has enough ventilation to keep everything cool over time. So far, so good. My tests with the EF-150 give the following results: Bare lamp: 8.0 With Jinbei reflector: 11.4 Extension at the widest point: 11.8 Extension at the narrowest point: 22.0 In general, such a modifier is for me a special modifier that doesn't apply to get used to something. all the time, so it must be a while. For those of you who use it regularly, if you need to tune it frequently, I don't know how long it will last, but I have nothing but my impressions to back that claim. As far as changing the light, it does what I was hoping for and doesn't reduce the light output at all.