First off, let me just say – this little gadget is LOUD. Like, "wake-the-neighbors" loud at 105dB. I tested it on my balcony door, and let’s just say my cat hasn’t forgiven me yet.

Setup? Ridiculously easy. Peel-and-stick adhesive (included) + no tools = done in 30 seconds. The magnetic sensor works even with a small gap between the pieces, which is great for slightly warped doors like mine.

The 2 remotes are clutch – one lives on my keys (yes, the keyring hole is annoyingly tiny), the other stays by the bed. Range surprised me – it arms/disarms from my parking spot below!

Cons? Batteries aren’t included (annoying but not deal-breaking), and one reviewer got a dud unit (mine worked perfectly though). Also, French users note: some wish it was even louder.

Verdict: For under $20? Absolute steal. Renters, Airbnb hosts, or paranoid plant moms (guilty) – this delivers peace of mind without wiring or subscriptions.