Best Wireless Mac Backup Drives
There's distinct advantages to purchasing an Apple Time Capsule
While 3rd party network attached drive solutions may prove to be just as reliable and simple to access - many simply prefer the Apple Way of doing things. For many though, getting a new Apple TimeCapsule may mean replacing an existing Apple AirPort Extreme Base Station
Mac Wireless Network Drives With AFP Support
AFP - Apple Filing Protocol is a MUST HAVE feature of any Mac network drive solution. AFP properly handles long or unusual filenames and characters that Apple users may have used naming files, and it's important that your wireless NAS Mac backup device can handle these properly, especially in a cross-platform network backup enviroment. Check the technical specifications to insure AFP is one (of several) supported file protocols for reliable OSX TimeMachine backup.
Convert A USB Drive Into Network Storage
Ipevo delivers a compact, simple gadget to turn ANY existing external USB backup drive into centralized Ethernet connected PC and Mac compatible NAS storage at a low price - around $60. Enjoy remote Mac backup from your MacBook or desktop through your current router's Ethernet port.
Ipevo Mini Network Storage Adapter
Mac, PC and Linux Compatible
Even more versatile - Iomega's drive converter supports both wired Gigabit Ethernet as well as Wireless connectivity:
Iomega EZ Media Backup
Complete Content Sharing
Simply connect Iomega's EZ-Media drive to your wireless network router or AirPort via it's ethernet port. Centralize your movies, photos and stream iTunes music files to use as a Media Server for your Mac, iOS gadget or Android device, and as your remote TimeMachine backup volume.
Mac Compatible NAS From Western Digital
One of the more elegant 3rd party network backup solutions - designed with iTunes Server support and other features with Apple computer users in mind - is the cross-platform NAS drive from WD:Western Digital My Book World Edition Drive

1TB, 1.5TB, 2TB Options
Iomega Home Media Network Drive For Mac
Another option to rival Apple's Time-Capsule:Iomega Home Media 1 TB Network Disk
Buffalo NAS Mac Drives
Buffalo LinkStation NASBuffalo Technologies has a long track record of good Mac product support. It offers several Apple compatible network backup drive options for Mac and iOS users in it's LinkStation product line - at very affordable price points.

