Swiss Made Magnetic Bases With Fine Adjustment. Locking strength equal to hydraulic Types Without fluids to leak out. Multi-nimble joint locks tight in any Position. All articulating joints lock simultaneously With the turn of one knob. Robust construction for Long life. Fits Dovetail and 3/8″ Stem indicators. Permanent Magnetic Base With On/off Lever. Two Models: Standard and new Giant Size. Dimensions: Total Reach: 21 1/2″, Main Post Dia.: 3/4″, 2nd Post Dia.: .500″, Main Post Length: 9 1/2″, 2nd Post Length: 7″, Base Dimensions: 2 1/8″ H x 2″ W x 3″ D.