While the armrest was a great aftermarket addition that smart forgot to put on the smart 451 this sunglasses holder is something they forgot to have on the smart but are nice enough to let you pay $55 to have this feature.
I paid the $55 and took the time to install and while its easy to install you might find it difficult to get the screws in as the steering wheel is somewhat in the way. After taking the time and installing the sunglasses holder I was really happy with the further growth of my smart.
Some people said they're sunglasses didn't fit but mine even though they are bigger then the normal sunglasses fit perfectly. If you have the big bling bling type sunglasses they might not fit but then again you probably wouldn't be driving a smart if you like bling bling style sunglasses.
Opening and closing the container is easy thanks to a magnetic latch.
They also made a little lip on the top so when its closes its easy to open up again. When opened it doesn't interfere with anything on the tray below.
Overall I really like this addition and having little holders/container/pockets on the car is fun. I hope that I can get more little holders, maybe something can be added to the lower part of the dash.