These ingenious clamps each contain two powerful rare-earth magnets. With the knob turned to the "on" position, the magnets align and cling to any ferrous surface. In the "off" position, the magnets counteract each other to release the clamp for removal or repositioning. The instant on/off toggle makes them ideal for custom jigs and fixtures.
They are available with either 20mm or 30mm magnets that exert 95 lb and 155 lb of force respectively. They have aluminum bodies with rubber-coated knobs for grip. The 20mm size mounts in a 1-3/16" hole, while the 30mm jig requires a 1-5/8" hole. Both install in material 3/4" thick.
An excellent alternative to traditional clamping methods.