I wasn’t going to waste my time with a review but you guys emailed me and asked for one. This Product does not fit snug into the downstem. Sometimes when I go to gently clean it with a q-tip after each use, the product will fall out of the downstem.I tried 3 different 10 mm down stems just to be sure. The only reason I’m not sending it back is because I already used it prior to noticing. My mistake for not checking first, your mistake for sending out faulty product. With all do respect a good team would catch something simple like that and this is why I won’t be returning as a customer.