Dealer hat off for a bit.....
Franc's Ovision worms are indeed excellent.
However the OPW Losmandy worm assembly is easily on a par and less expensive by a good margin.
They both work well by using similar methods to null-out any tangential play in the worm assembly bearings....(my personal OPW modded G-11 returning around +/- 2 arc sec).
In any event, installing the Ovision or Losmandy OPB is *the* one upgrade you can make to a G-11 that seriously improves its performance
