When heading out for a hike, you usually have the option of stuffing your first aid and emergency gear into a backpack.

But that’s not the case when you’re going for a trail run. Trail runners typically head out the door with nothing more than a hand-held bottle or ultralight vest to tote all required supplies—and those tiny pockets fill up quickly. So here are some of the best small-sized must-haves to take with you on your runs.

Water

Water is a no-brainer—you should be bringing some with you no matter what time of year it is. Fill up your bottles and/or bladder with more water than you think you’ll need, especially in the hot summer months. That way you’ll have enough to keep you hydrated if you don’t make it back as quickly as anticipated. It’s also a good idea to slip a couple of water purification tablets into your vest for an emergency. These are extremely small and weigh next to nothing, but they’ll make fresh water you encounter en route drinkable.

Extra Fuel

Squeeze a few more energy-packed snacks into your vest. Keep an extra bar or gel zipped away because having the extra fuel may give you the boost you need if you end up in an emergency situation.

Bear Spray

For those trail runners who share territory with bears, don’t even think about leaving home without a can of bear spray. Check the expiration date to make sure it still works. Keep the can in an easily accessible place—you might even consider picking up a belt specifically made to carry the stuff.

Emergency Blanket

Mylar emergency blankets don’t weigh much and are easy to slip into a pocket. They’ll help you out in a pinch, like if you end up injured and having to wait for help. They have more uses than simply being used as a blanket: use as a makeshift lean-to, as an emergency signaling device, as a compression bandage, etc.

Headlamp

If you’re planning a multi-hour run, it’s a good idea to bring along a headlamp, even if you intend on returning in daylight. If you get caught in the dark, it can be very difficult to find your way back in the pitch black. A headlamp is especially useful in the autumn months when the sun starts to set earlier than you’re used to.

Whistle

A whistle is another tiny tool that doesn’t weigh much but that can be invaluable in an emergency. Pack one along to help attract attention and signal if you find yourself in trouble.

Multitool

A multitool will help you in any number of emergency and non-emergency situations—from cutting clothing into makeshift bandages, to making wood shavings for an impromptu fire, and beyond. Carry one with you and you’ll likely be surprised at how often you use it.

Athletic Tape

A small roll of athletic tape is invaluable for many trail-related ailments. Though it doesn’t replace a full first-aid kit, the tape will help in stabilizing a twisted ankle and as an improvised bandage. It can also be used to repair a pack or jacket on the fly.

On that note, it’s well worth investing in a wilderness first aid course. Even an introductory weekend-long course will give you the confidence needed to tackle potential mishaps on the trails—and that doesn’t take up any pocket space at all.