Let's talk about these tiny white magnetic door sensors. First off, they're smaller than I expected—about the size of a quarter—but don't let that fool you. The ABS plastic feels sturdy, and the white color blends seamlessly with my door frames.

Installation was straightforward. The recessed design means they sit flush against surfaces, making them nearly invisible. I used them on both my front door and bedroom window, and the 25cm cables provided just enough length for clean routing.

Performance-wise, they work exactly as described: circuit closes when magnets are near (door/window shut), opens when apart (door/window open). The 20-30mm actuation distance is generous—no need for perfect alignment. They've been reliably triggering my home alarm system for weeks now.

However, I did notice one quirk: like some reviewers mentioned, extremely strong external magnets can potentially interfere with their operation. Stick to the included magnets or similarly sized ones to avoid issues.

The big question is durability. While mine are holding up fine, another reviewer reported units burning out quickly. Time will tell, but at this price point for 3 sets, they're worth trying as an affordable security upgrade.