After trying this coupling with my router bits, I've noticed a significant improvement in accuracy and smoothness of my cuts .The flexible design allows for better ALIGNMENT and reduces vibration. The only downside is that it requires extra care when cleaning to prevent buildup in the bearings..
Using parts from a kit to control the Z axis on a CNC machine. A very well thought out kit, although not specifically designed for my use case it contained all the parts I needed. The only thing I can complain about is that the ball bearings in the sliding blocks loosen easily and tend to fall out when the rail shaft is inserted. Just be very careful when inserting the rail shaft or you may scour the ground for worn ball bearings.