Dr. Beat Series (DB-30/DB-60/DB-90)

DB-30
http://www.roland.com/products/en/DB-30/
The DB-30 helps musicians take their music to higher levels by offering a set of features that defies its diminutive size. Much more than just a simple timekeeper, this pocket-sized metronome can lay down a variety of rhythm patterns and time feels to practice along with, and it has a few timekeeping tricks up its sleeve as well.
DB-60
http://www.roland.com/products/en/DB-60/
The new DB-60 is priced to please, yet it doesnt disappoint in the feature department. This handy little timekeeper can lay down the click in style. For practicing a particular song, its important to set the metronome to match the feel of the song, so along with the basic metronome functions, the DB-60 offers a variety of rhythm patterns such as 8-beat grooves, waltz, bossa nova, and more.
DB-90
http://www.roland.com/products/en/DB-90/
The new DB-90 is loaded with quality sounds and drum patterns to make your practice sessions less mundane and more musical. Theres a Rhythm Coach function with an onboard mic, a reference-tone function for tuning, an Instrument input, MIDI input, and other handy tools to make learning fun and effective.