[MATERIAL]: The strut is made of aluminum and the base is cold drawn steel. [SIZE]: Fixed arm height: 6.9''; Extension arm length: 6.3''; Magnetic Base dimension: 2.30" L x 1.98" W x 2.18" H; Holds 3/8" stem and lug back; Holding Power: 135lbs. [MAGNETIC BASE]: The magnetic bracket adopts switchable permanent magnet, which is easy to install on the metal surface.V-groove base for easy installation on cylindrical parts. [UNIVERSAL KNOB]: Flexible, strong and precise rotary joint can adjust the support rod to any direction and fix it firmly. [APPLICATION]: Used to maintain the position of a dial indicator or test indicator etc. during measurement operations.