With two magnetic faces and large vee. Heavy duty with universal clamp and fine adjustment. Mounts: 1/4" I/D lug, stem/spigot diameter: 4mm, 8mm, 3/8" without bush. Base dimensions: 60 x 50 x 55mm. Column height x dia.: 175 x 12mm. Crossbar length x dia.: 165 x 10mm. Clamp ring: 6.35mm. Magnetic pull: 50kg.