Let me start by saying these little white magnetic switches are *ridiculously* affordable for a 5-pack. I installed them on my basement windows and backyard shed doors, and they've been quietly doing their job for months now.

The installation was straightforward - the included screws held firm even on slightly uneven surfaces. The 25cm cables gave me enough slack to route wires neatly, though I wish they were slightly longer for some awkward window placements.

Now about that famous 'backwards labeling' issue everyone mentions: Yes, the NO/NC markings are indeed reversed. But here's a pro tip - just test them with a multimeter before wiring (took me 30 seconds per switch). Once you know which contact does what, they work perfectly as door/window sensors.

The magnetic sensing distance is consistent at about 1/2 inch in my testing. They reliably trigger my home alarm system every time - no false alarms so far. The plastic housing feels durable enough for indoor use, though I wouldn't trust it unprotected in harsh outdoor conditions.

Two minor gripes: The switches are bulkier than I expected (about the size of two AA batteries side by side), making them slightly visible on slim window frames. Also, as one reviewer noted, strong nearby magnets can cause interference - keep them away from speaker systems or heavy-duty tools.

For under $15? Absolute steal. Just approach them knowing you'll need to verify the contacts yourself, and you've got an incredibly cost-effective security solution. I'm using three of my five switches currently - keeping the extras as backups!