We really did not care about the gram savings the hole in the center provided.....
It was the extra width of these clamps we really liked. These clamps let you use any standard braze-on style front derailleur on your bike if you don't have a fixed braze on mount. Available in both 31.8 or 34.9 diameter, which fits a big range of bikes.
We like them on carbon bikes as they provide a lot of extra area for pressure distribution versus the narrow band-style clamps-on front derailleurs. CNC machined and black anodized. Torque to your frame manufacturer's specs or 4 nm.
We have found that a little carbon paste on the inside of the clamp prevents slipping at the lower torques needed by composite or light alloy frames and is strongly recommended.