If I remember my shiftmate chart correctly the #3 will allow you to use a Campagnolo 10 speed ergo with a shimano 10 speed cassette and a shimano rear derailleur (8,9, or 10 speed road - except tiagra 4700 or 9 speed mtb).

Edit: I'd remembered incorrectly. You want a #3 shiftmate according to their chart. I originally said #2. #2 will only let you do 9 speed.

Shiftmate 3

For mixing shiftersShifterDerailleurCassette type and speedPulley groove size that cable entersShimano 9 speedShimano 9 speedShimano 6 speed freewheelSmallShimano 9 speedCampagnoloCampagnolo 9 speedSmallShimano 10 speed road*CampagnoloCampagnolo 10 speedSmallShimano 10 speed road*Shimano 10 speed road*Shimano 7 or 8 speedSmallShimano 10 speed MTNShimano 10 speed MTNShimano 7 or 8 speedSmallShimano 10 speed Tiagra 4700Shimano 10 speed Tiagra 4700Shimano 7 or 8 speedSmall2001 and newer Campagnolo 9 speedShimano road to 10*, MTN to 9 speedShimano 9 speedLargeCampagnolo 10 speedShimano road to 10*, MTN to 9 speedShimano 10 speedLarge

*Except Shimano Tiagra 4700 10 speed shifters and rear derailleur
Edit#2: that table didn't insert with formatting, try this link: http://www.jtekengineering.com/resou...compatibility/