How does Manny Ramirez always hit with such power?

when manny homers you know its gone. like some batters it will come real close to not making it over the fence but with manny his are well over and you know it aint staying in the park. but manny isnt a huge guy and doesnt look like a body builder either so how does he get so much power on those home run swings? and do you think manny is a strong guy cause his arms and forearms dont look to big but maybe i am wrong.