Nice product, I don't know how is working but is very sensitive, don't even needs to touch it, it starts whistling very loud even if you get 5 cm close. It hangs on my door handle and I find it very useful. I still don't know anything about the battery life but I will keep you updated.

Nice product, I don't know how is working but is very sensitive, don't even needs to touch it, it starts whistling very loud even if you get 5 cm close. It hangs on my door handle and I find it very useful. I still don't know anything about the battery life but I will keep you updated.

Nice product, I don't know how is working but is very sensitive, don't even needs to touch it, it starts whistling very loud even if you get 5 cm close. It hangs on my door handle and I find it very useful. I still don't know anything about the battery life but I will keep you updated.

Does what it says. And for the price you can't beat it. Would be good for use by females staying at motels and college dorms. This device is very sensitive and loud.

Does what it says. And for the price you can't beat it. Would be good for use by females staying at motels and college dorms. This device is very sensitive and loud.

Does what it says. And for the price you can't beat it. Would be good for use by females staying at motels and college dorms. This device is very sensitive and loud.