Every MakerBot owner / user needs one of these on their key ring.
This key fob has an outer / middle / inner ring which spin freely and independently from each other. This makes it a great little 3D printed things that shows what is possible... a real conversation starter that goes everywhere you go.
Easy print with designed in support... on a Replicator 2 the support comes away easily and cleanly leaving the middle and inner rings to spin freely... give it a quick spray with some silicone lubricant (non-greasy and dry finish) to make it spin really well and similar to a bearing.
To make it multi-coloured (as pictured) change the filament at 2mm and again at 6mm when using Raft (approx. 1mm thick). If not using Raft then change it at 1mm and 5mm.