Original price was: $10.95.$9.31Current price is: $9.31.
Two functions in one small device: hang it on a door knob and it sounds automatically if someone touches the knob, or carry it with you and pull the chain to trigger the alarm manually. It’s 120 decibels — loud enough to be heard clearly from a distance. Runs on a single 9V battery and requires no installation or setup beyond hanging it or putting it in your pocket.
Most personal alarms only do one thing. This one does two. Hang it on a door knob — works on non-metallic doors — and it triggers automatically if someone grabs or turns the knob. That’s useful for hotel rooms, dorm rooms, or anywhere you want a heads-up before someone gets through the door. Take it off the knob, put it in your bag or pocket, and the pull-chain converts it to a standard personal alarm you activate manually.
It’s a practical combination for anyone who travels, lives in shared housing, or just wants more than one layer of awareness without carrying two separate devices.
It makes a lot of sense for travelers staying in hotels or Airbnbs where you can’t install anything permanent. Hang it on the interior knob before bed, and you’ve got a simple early warning system that requires no tools, no adhesive, and no damage to the door.
Students in dorms get a lot of use out of these too. A single-occupancy room doesn’t always have great locks, and the door knob sensor adds a layer of awareness without requiring any approval from housing.
It also works well as a standalone personal alarm for walks, runs, or commutes — pull the chain, the alarm sounds, and you let go of it so both hands are free.
Choose this 2-in-1 alarm if you want:
Consider something else if you need:
In door mode, the device hangs on the knob. Any movement or contact with the knob completes the sensor circuit and triggers the alarm. That gives you a few seconds of awareness before anyone gets the door open — enough to react, call out, or move to a safer position in the room.
In personal alarm mode, the pull-chain breaks the circuit when you yank it, which sounds the alarm. It’s a simple mechanism and a reliable one — no batteries to charge, no Bluetooth to pair, no app to open. The 120dB output is comparable to a smoke detector at close range. It’s genuinely loud.
The single 9V battery powers both functions. Battery life depends on how much the alarm actually sounds — in standby mode monitoring the door, it draws very little current and lasts a long time.
| Feature | 2-in-1 Door/Personal Alarm | Door Stop Alarm | Window/Door Contact Alarm | Personal Alarm Only |
|---|---|---|---|---|
| Door Protection | Yes ✓ | Yes ✓ | Yes ✓ | No |
| Personal Carry Mode | Yes ✓ | No | No | Yes ✓ |
| Blocks Entry | No | Yes ✓ | No | No |
| Installation Required | No ✓ | No ✓ | Sometimes | No ✓ |
| Sound Level | 120dB ✓ | 120dB ✓ | Varies | 100–130dB |
| Best For | Travel + daily carry | Hotel room security | Home window/door monitoring | Walking, running, commuting |
Dimensions: 4¼″ x 2¼″ x 1″. Weight: 0.23 lbs. Color: Black. Power: one 9V battery (not included). Includes pull chain for personal alarm mode. Works on non-metallic door knobs only. No installation hardware required for door mode. Compact enough to slip into a jacket pocket, small purse pocket, or day bag side pouch.
For the price, it’s a genuinely versatile device — one alarm that works on your door at night and in your pocket during the day. Hard to argue with that combination.
The door knob sensor works by detecting contact or movement on the knob. Metal knobs can interfere with how the sensor reads that contact, resulting in false triggers or the alarm not activating reliably. Non-metallic knobs — which are common in hotels, dorms, and most interior residential doors — provide a consistent surface for the sensor to work properly. If your door has a metal knob, a door stop alarm or contact sensor would be a better fit.
The pull chain is designed to be reinserted to reset the alarm after it sounds. Pulling it triggers the alarm; reinserting it stops it. The chain stays with the device — it doesn’t disconnect permanently. This means you can test it, reset it, and carry it as a personal alarm repeatedly without needing any replacement parts.
In standby mode — just hanging on a knob, waiting — the current draw is low and a fresh 9V battery will last quite a while under normal use. Actual life depends on how often the alarm sounds, since that’s when power draw spikes. A good practice is to test the alarm every month or two and replace the battery once a year or whenever it sounds noticeably quieter than usual.
Yes. The two functions are independent. If you only want a pull-chain personal alarm for walks or commutes, just carry it in your bag or pocket without ever hanging it on a door. The door knob function doesn’t need to be used for the personal alarm to work. It’s the same device either way — you just use whichever mode fits your situation.
| Decibles | 120 db |
|---|---|
| Battery | One 9 Volt |
| Color | Black |
| Included | Pull Chain |
| Weight | 0.23 lbs |
| Dimensions | 4 ¼" x 2 ¼" x 1" |
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