Feature●Holds 3/8" and dovetail.●Noga unique central locking mechanism with spring loaded bearing.●Powerful 70 lbs. on/off magnetic base with fine adjustment on the base.●Bottom arm length: 2.20"●Top arm length: 2.00"Description Noga NF10433 Nogaflex Magnetic Base 70 lb. Holding Power Dial & Test Indicator