Seat gap filler was a bust. It was too wide for comfort. Will try other location or type.
I had my cell phone, credit card, etc. fall through the seat gap one too many times and (after seeing ads, since "they" are always listening, lol) decided to get the Drop Stop gap filler and it moves with the seat pretty well. It does not offer any additional storage, but does offer some additional space (allows the front driver/passenger to put the phone or other items next to them). I got the 2-pack (4 total gap fillers) for like $20 on Amazon, so I put them in my wife's vehicle too and they have served their purpose. It's also good for those that work/eat in their vehicles like I do sometimes as it prevented a spill or two from getting down in the gap, which would have been a total pita to clean up. For those of you do work/eat in your vehicle, you can get a steering wheel desk/tray that makes life much easier too.