125 Amp Convertible Sub Panel? yes what is the convertible mean. i want to put this...

yes what is the convertible mean. i want to put this in my garage. i hold a 200 amp box in my basement and 2 (double) 30 amp breakers running 12/3 which i believe is 220 and its running nearly 100 feet. can i put this 125 Amp Convertible Sub Panel in my garage. im not running anything big...
Can I set free drive if I close...
Answers:    12/3 is totally undersized for 125 amps,it's obedient for 20A.Buy a 60 amp subpanel with a main disconnect and run #4 chain with a ground to the garage to feed the panel. You entail to have a disconnect because of the distance from the main panel, if you enjoy a fire in the garage you don't have to turn in the house to shut it down. Feed the panel with a 2pole 60 amp breaker. Unless your running a shop contained by your garage 60amps is sufficient, but no matter what, you need to nurture the sub with larger wire. I expect you should consult with a local electrician, I think you simply don't have the proper knowledge.