Tiny top, big spin. This stainless steel precision spinner is about half the size of your standard key, so it won't overwhelm your keychain or make it look like you have a side boner if you stuff it in your pocket, and if its Japanese maker is to be believed, it's "better than the Inception top." Not sure if that means functionally, aesthetically, or in ability to determine whether or not you're in someone else's dream, but there you go.
At least in ease of spinning and spin time the top keychain is clear that it is accessible to everyone and will keep you mesmerized for about 2 minutes per twirl. A self-balancing design enables novices to get the top going with little effort, and the top will right itself to vertical even if initially spun in a crooked position.
The top weighs 0.3 ounces and includes the key ring pictured.