This is a fairly basic metronome with a range of tempos from 40-208BPM in the key of either A or Bb (user selectable).
The build quality is okay, fairly solid plastic construction, but nothing amazing.
Feature wise you have a tempo control wheel, volume control, headphone out and a selectable key of either A or Bb for the click. There is also an LED at the top which is synced to the tempo, handy should you be playing loud.
It's a great item to keep near your guitar rig for practice sessions, but if you have a smart phone you could probably save a few pennies and use an app. At least then you could have some tap tempo options.