Hi Jules , I am fairly sure that any generic duel axis drive will fit your mount ,
, these mounts are all Vixen clones , and weather they are any of the Chineese brands they will fit , $199 - $249 is the going price for these , either Andrews Comm , or Bintel , sell them .
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They make viewing a breeze .
I have a few set of these drives and , driving the mounts of mine now , for 5 years now are both , the Vixen and chinese versions , and they both aint missed a beat , some are 6 volt , and some are 12 volt , so be weary of the after market power sources and check the imputs .
My Vixen drive is 12v , and my Synta is 6v and they both work really well . ( both Duel axis drives) and over the years I have not really touched either.
Truthfully tho , the Vixen is a better system all round .
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Hope this helps mate .
Brian.