I am comparing this (cheaper) electromagnet to a Stronghands magnet. The magnetic pull seems less effective for 90 degree grips, mainly due to its polygonal shape, so I think it's really only for corner grips.
Pros
β EASY TO USE: On/off switch adjusts the magnetic strength of the welding magnet. Just fixed and removed. Fully enclosed to protect against metal dust. Easy to clean after wiping the magnetism.