It's easy to forget simple things when you're on the go. You may have forgotten to turn off your bathroom light before leaving the house, or you left your notebook at home instead of putting it in your backpack. Sometimes forgetfulness is nothing more than a minor inconvenience, but other times it can be more serious.

You may have forgotten to turn off the burner on a stove or not locked your car after leaving it in a busy parking lot. If you are a city dweller, you may have forgotten a self-defense tool.

Cities can be dangerous, and it's always in your best interest to stay prepared, whether it's by staying aware of your surroundings or by knowing where you're going and informing others of your location in the meantime. A simple way to stay prepared, in addition to staying alert by listening and monitoring your surroundings, is to carry a self-defense tool.

This could be a baton, a knife, or pepper spray, all of which can be easily used to protect yourself from assaults and robberies. Even better, some of these tools can be used to intimidate potential criminals and scare them away before they can approach you.

But not all self-defense weapons are bulky items that need to be carried like a shoulder gun in an old western movie. Modern self-defense tools are compact enough to be carried directly on your key chain. Placed next to your keys, these safety gadgets are immediately accessible, keeping you safe wherever you are.

Here are seven of our favorites that will keep you safe in any situation:

  • Brass knuckles

Forget brass knuckles, we're not in a bar fight. Knuckle guns are easy to handle and can be attached to a key chain for immediate use in case of danger. These handy gadgets keep you safe, whether you're commuting to work in the morning by train or walking to your car late at night. The rigid joints and sharp edges are sure to stop any assailant in their tracks.

  • Knives

Knives are a great option for anyone looking for the ultimate form of protection. Easily stored on a keychain, you can grab a knife and be protected in seconds. Just be careful how and where you use this safety tool, as each state has different laws on concealed carry of knives.

  • Pepper Spray

Sometimes it's in your best interest to stay protected while keeping your distance. Keychain pepper sprays give you that option. These small cans can be easily carried on you, without the weight and size of normal pepper sprays. Although the spray distance tends to be shorter than larger devices, you will have a small protective device that you can carry without raising suspicion.

  • Stun guns

The best self-defense gadget is one that can scare off an attacker or incapacitate them completely if they don't give up, even after you warn them to stay away. Stun guns give you this luxury. The electrodes emit a terrifying, shocking, rattling sound when activated, which is sometimes enough to scare a criminal away.

But if he is undeterred, the device can be used to emit millions of volts of electricity into his body, causing temporary paralysis. This stunning effect can give you time to get to safety or gather a crowd of people nearby who can apprehend the criminal until the police can arrive and take control of the situation.

  • Expandable batons

Looking to keep some distance while fighting an attacker? Expandable batons offer this, allowing you to stay safe with a device that can increase in size as you need it. The best part about this weapon is that it looks completely harmless, not drawing attention to itself until it is used. And, once enlarged, this weapon can be used to protect against an assault or robbery.

  • Panic Alarms

Easily connected to a key fob next to your car and apartment keys, panic alarms are simple devices that can bring you to safety when needed. These devices are simple personal protection solutions that work by simply pulling a chain or pressing a button. Once activated, this device emits a high-pitched scream of over 100 decibels in volume.

The thing that criminals hate most is attention, as it increases their chances of being caught and facing charges. By activating this device, you will immediately draw attention to yourself and them, which will hopefully cause them to flee, leaving you protected.

  • Kubotans

Considered pressure point weapons, kubotans are handheld sharp devices that can be driven into a person's flesh for maximum protection. Hitting a nerve or soft tissue can result in temporary paralysis and intense pain, while hitting a fairly strong bone - in direct contact with the clothing in between - can even result in a fracture. This non-lethal option is a great alternative to knives, having a similar shape while giving you maximum force and intensity when trying to fend off an assailant.

Keep personal safety devices on hand

While it's easy to forget simple things when you leave the house, that shouldn't be the norm when it comes to your personal safety. Rather than taking chances, have a keychain safety gadget on hand. These easy-to-carry self-defense tools can provide you with some form of protection at all times, no matter where you are. Consider getting one today so you're ready before someone catches you by surprise.