Trek-Tech MagAdaptor SD (Screw Down) Heavy Force Adaptor for DSLR Cameras and Other Optical Devices Rare Earth Neodymium Magnet has no effect on Digital Storage Media. Heavy Force Screw Down MagAdaptors are great for DSLR cameras, Spotting Scopes, and other heavier optical devices. Comes with a 3mm Allen Wrench Because of its floating screw, it can be attached more tightly using the hex wrench insuring that it will not come loose from the device.