This question already has an answer here:
Is the word of necessary? For example:
Take the towel off of the counter.
Take the towel off the counter.
It is correct and acceptable in either case. The use of the word 'of' in that case is not necessary, but when used I believe it to be superfluous.
Note: Take consideration that TrevorD advises against the use of off of because in British English, since it is neither correct nor acceptable. I am not British so I cannot speak to this, but keep it in mind. I have definitely heard this in American English though. e.g. Get your hands off of my stove!
Although it appears in the Journal of Samuel Pepys, written in the 17th century, using "Off of" for "off" is an error in standard modern English.