With their "nothing but the screen" appearance, Apple's recent iMac models are marvels of sleek design. The downside to this approach, however, is that if you need to connect peripherals, all the system's ports are hidden in back. This is fine for ports you access infrequently, but for devices you connect and disconnect often--for me, USB flash drives and a few specific peripherals--it can be a pain.
I've got a USB hub connected to my Mac (more on that in a future Gear We Love column), but the hub stays hidden behind my iMac, too. What I want is a single USB port on the front of the computer--like the ones on older Mac Pro models--for quick, temporary connections.
I get exactly that with BlueLounge's $15 Jimi USB Port Extension. Made specifically to work with late--2012 and later ("slim") aluminum Unibody iMacs*, the Jimi plugs into one of the USB ports on the back of your iMac and extends that port around to the front--the extended port sits just below the bottom edge of your Mac.
Unlike a simple USB extension cable, the Jimi's USB port feels almost as if it's part of your iMac: The body of the Jimi is stiff, and a little tab on the top of the Jimi's port end fits into one of the air-vent holes on the bottom of the iMac, so the Jimi's USB port doesn't move much when you insert and remove USB plugs.
Because of this air-vent-tab design, the Jimi is stable with only three of the four USB ports on the 27-inch iMac--the fourth port, indicated in the image here, doesn't have an open air-vent hole below it. But that's a minor issue, as it's easy enough to arrange your USB plugs so the Jimi gets one of the three compatible ports, and the Jimi doesn't block adjacent ports. (The Jimi works with all four USB ports on the 21-inch iMac.)
The Jimi is a clever accessory that solves one of the annoyances of the current iMac's design. You can even use multiple Jimis together to extend more than one USB port to the front. Now if only Bluelounge would make a version of the Jimi for the iMac's SDXC-card slot...
* Although the Jimi is designed for 2012 and later iMacs, it also works with some older aluminum iMacs, though you don't get the secure, snap-in fit. For example, I tested the Jimi with a 2010 27-inch iMac, and it does a nice job of providing an easily accessible USB port; however, the tab on the port end of the Jimi doesn't secure to the bottom of these older iMacs, so you need to hold the Jimi with two fingers whenever you connect or disconnect a USB device or cable, and the Jimi doesn't extend all the way to the front of the iMac--it's recessed about three quarters of an inch, thanks to the older iMac's thicker profile.