A magnetic lock holds a door closed with an electromagnet in the frame and a steel armature on the door. It is fail-safe: power loss releases it. Because it has no moving latch, it needs a request-to-exit device and careful attention to life safety and local code.
Maglocks are simple devices with complicated rules. Holding force is easy to compare; permission to use one on an egress door is the question that decides the design.
Fail-safe, and what that means
Removing power opens the door, which is right for a fire alarm and wrong if the power is removed deliberately. Pair it with a request-to-exit sensor and a monitored release.
Code and life safety
Many jurisdictions restrict maglocks on paths of egress and require sensors, signage and a manual release. Confirm the requirement with the authority having jurisdiction.