Duo Magnetic Clamping Blocks have two opposite magnetic sides and are designed for workpieces to be fixed on steel surfaces like welding and clamping tables. Several Duo Magnetic Clamping Blocks can also be connected to each other via the inside hexagon of the switching shaft in order to clamp longer or larger workpieces. The activation is effected via the detachable switch wrench with only 90° switching travel, the surfaces of the duo magnet are completely nickel-plated. The two differently shaped clamping sides of the Duo Magnetic Clamping Blocks can be used to hold almost any workpiece geometry, regardless of whether round material, sheets or even profiles are to be clamped. Duo Magnetic Clamping Blocks are the optimum clamping devices to clamp quickly, flexibly and without interfering contour on welding and clamping tables for drilling, deburring, welding or thread cutting.