Unfortunately, the Solofill doesn't really work as advertised, at least not on the Keurig model we have. There's no model number to be found (whoever bought it or installed it probably does) but I suppose it must be one of the models the Solofill web site lists as "incompatible." The result is that as much water leaks around the filter as through it, and splashes on the counter as well as on the drain stand your mug rests on.
Obviously, that's not gonna be useful, so I went to Amazon to look into returning it. Clicking the return button on the order page immediately brought up a message that this item isn't returnable. I guess it falls into the grocery and household category. I sent a feedback message explaining what happens when I try to use the product about an hour ago.
Just now, I got a response that my purchase price has been refunded, and I can dispose of the defective item however I see fit. (If any of you has a Keurig that's not incompatible, you're welcome to it.) Dan says he got a Keurig-labeled filter at Target that works, so I think I'm going to run up there to grab one, as well as to get some snake food.