I bought this Lil Shredder Icon 20" MTB for my daughter to start her mountain biking on. If your not familiar with the bikes try:

http://lilshredder.com/

It has shimano deore hydralic brakes, and air fork, shimano 1x10 rear cassette, Loaded hubs, stem, and CF bars. It weighs just at 20.1lbs. It has a couple scratches but nothing major. It shifts and breaks as it should.

It fits a 6-10yo depending on the kid of course. My daughter used it at the over the hump series for a couple of years, outgrew it, and passed it along to her sister who did the same thing.

It's an awesome bike, only lil shredder and trailcraft make true MTB's for kids.