You might want to get Tower Pro sg90. Is way better and cheaper then Esky servo. Ebay have a tons there. Or go Hobbycity look for HXT900, which cost you $3.50 each and is a direct duplicate of sg90.

If you are interested in either of it, I can sell you mine, is brand new. No idea why I bough x10 HXT900 and x4 sg90 which all has been sitting in the box for more then a month