Apple computers are pretty good, unfortunately their Thunderbolt ports aren't, they're way too loose. Any movement will rattle the connector and "break" the connection, not super cool if you're using the Thunderbolt for file transfer or for an external monitor. So we came up with this little gadget to secure both the Thunderbolt and MagSafe 2 connectors together, effectively providing the strength of the MagSafe magnet to the Thunderbolt connector. As a result nothing moves, and everything works all the time :-) This was designed to work with a Macbook Pro Retina 15-inch (Late 2013) i'm not sure if it will work on others. The cable fit very tightly inside in order to provide a firm hold on the connectors, if your printer makes it too tight you may choose to scale it by a few percents. I've made the Two and Three cable dock, for those who wish to use both Thunderbolt connectors. Enjoy. It can also be purchased on Shapeways : http://www.shapeways.com/shops/PrototypeAsia