These friction arms come with a large center locking knob to lock all 3 movements, and variable friction and locking is obtained by adjusting the knob.
The rod clamp also have 3/8" female hole for professional use....
Max. Load: approx. 2kg
Attachment: 1/4" male and 15mm rod clamp with 1/4" and 3/8" female hole
Length (Max.): approx. 17cm