There's a special edition Ritchey Torque Key in Sigma Sport that comes with a selection of replaceable bits for c. £20 vs the standard one that only has one non-changeable M4 bit.
Does 5nm which is all you really need for carbon bits if you have assembly paste and it fits in a pocket for fiddling with your position when out on the road for first few rides.
As I understand it all the cheap torque £50 wrenches by Giant PRO BBB are the same item just rebadged, that PRO one does look different but no idea if any better.
There's a special edition Ritchey Torque Key in Sigma Sport that comes with a selection of replaceable bits for c. £20 vs the standard one that only has one non-changeable M4 bit.
Does 5nm which is all you really need for carbon bits if you have assembly paste and it fits in a pocket for fiddling with your position when out on the road for first few rides.
edit
this is the fella
http://www.sigmasport.co.uk/Product/20622/ritchey-special-edition-torquekey-with-bits.asp
As I understand it all the cheap torque £50 wrenches by Giant PRO BBB are the same item just rebadged, that PRO one does look different but no idea if any better.