Rotary post holders allow posts rotating post axes in 360owithout changing their heights; fine processing V-shaped trough with center hole axial will have steady locking and no horizontal positioning when post heights are adjusted; they have flexible steel ball design so that the condition of posts fixed in V-shaped trough at no locking time is the same with that of at locking time; rotors are connected stators by precision bearing with comfortable rotation and high precision; posts and rotors may be reliably locking; three specifications meet different needs of height adjustment.
