Review on K&F Concept 18-Piece Filter Ring Adapter Set, Camera Lens Filter Metal Stepping Rings Kit - Black (Includes 9-Piece Step Up Ring Set + 9-Piece Step Down Ring Set) by Paul Tilden

They are good and serve me well. I have a lot of 77mm filters, I have used these adapters to mount my filters on 67mm and even 49mm lenses, they work well for this purpose. They don't screw onto the lens very easily though, you have to align and align many times until you get the result you want, which never happens to me when using my decent Hoya and black and white filters (I think I've seen that somewhere Aluminum is not the best material for precision fitting, thermal expansion can affect alignment so you would expect this from a cheap quality material meant to do the main job and brass costs a lot more which is what is used in B+W filters). I would recommend them except in two cases: you need to use them all the time or you can't afford to play around with them during an important shoot (note that I'm not a pro but a gamer so my advice is based on mine needs).