Flexbar Universal Work Positioners

It's an excellent dial indicator holder.
All metal parts used.
Precision angled bearings interface and lock the ball precisely with a small turn of the locking knob. Excellent rigidity factor.
Self-compensating, no need to disassemble to re-establish tension (sa with other designs).
Right angle notch (for 90º positioning) can be swung to any point 360º and then locked.