Items

Items are spawned in around the map in all game modes, and certain perks can give you a certain item to start with. Most items can be used in your hand, the same slot your weapon goes to, which means you can only carry a maximum of two items or weapons. There are some special items that can be equipped in the Gear slot. Items and weapons can spawn in the same location on maps. There is no true limit for how many of a certain item can spawn per map.

Normal Items
These are the items that are not equipped in the Gear slot. You use them as you would use your weapon, pressing left click to use said item, unless the item has multiple uses.

Fire Extinguisher
Fire Extinguishers can spawn at any item spawn location on the map or can be given to a user of the Janitor perk. Like weapons, this item can be "fired" and can over heat.

When used, they spray a flame extinguisher, which can put out fire from Flamethrowers. If spray on a Spaceman, it will strangle them (unless they have the Intake Valves perk), causing their oxygen to go down, even while indoors. When sprayed on a disguised Monster, it causes their Disguise meter to run down slightly faster.

Welder
The welder is an item used to repair and weld certain features around the map. They can only be spawned in by someone using the Welder perk, which is also required to be able to use the welder's alt-fire.

The welder's primary fire can be used to fix cameras, doors, and sentry turrets. It repairs 15hp per tick. It can also be used to damage players, however the damage is too minimal to be used as a weapon. The alt-fire is weld, which is used to weld doors shut. Welded doors cannot be opened by any means, and must be destroyed in order to open them.

Stun Baton
The stun baton is an item that can only be spawned in by someone using the Warden profession (1.13) and looks similar to the Half Life 2 Metro Cop Stun Baton. It can be swung by pressing primary fire, and can damage players, dealing five damage to Spacemen and 20 damage to Monsters (and can break/damage chitin). In addition to being damaged, it also electrolocks players, causing them to be unable to interact and shoot. Unlike most weapons, however, the stun baton can only be used four times before disappearing. There is also a delay between which you can stun someone that has already been stunned.

Health Syringe
The health syringe can be found at any typical item spawn location on a map. You can use primary fire to heal whoever you're aiming at, assuming you're right beside them. If you use alt-fire, it will heal yourself. It will always heal 50 damage. If used on a disguised monster, it will force the monster to transform, unless they have the Antibodies perk, which will deplete their disguise meter by 75 points.

Grenades
There are three grenade types, the noise grenade, the stun grenade, and the frag grenade. They are all thrown by primary fire, however the frag grenade can be ignited prior to throwing. All grenades are thrown in an arc and bounce around the world. The frag grenade and the stun grenade can pop open airlocks if thrown near them, causing them to suck out any unfortunate spacemen caught in the way.

Noise Grenade
As the title suggests, when thrown, this grenade emits various sounds, mainly pistol and AR/LMG gun fire depending on your distance to the grenade, and monster footsteps if you're near it. You can shoot the noise grenade with any normal weapon, causing it to turn off. Sentry turrets will also automatically disarm any noise grenades that wander in its range. They can be used as a diversion for the monster as a distraction or to cause confusion.

Noise Grenade - 'Thank you for participating in this emergency alert test.'

Stun Grenade
Stun grenades can be thrown by using primary fire, after two seconds it will detonate, stunning all players that are within its range. The stun lasts for five seconds, blinding and deafening the stunned person. If a disguised monster if close enough to the grenade, this will force them out of their disguise. If the monster has the Membrane perk, they will be unaffected by the stun grenade, regardless of distance to the stun grenade or if they're in monster or spaceman form.

Frag Grenade
Frag Grenades are like stun grenades, however their explosion is far more lethal. The frag grenade will do 275 damage to spacemen, monsters, and buildings/objects. Unlike the other grenades, however, you can prime the grenade by using alt-fire, which will "cook" for a few seconds and then explode, causing the igniting spaceman to explode with it. For those suicidal spacemen that wanna take one for the team, the frag grenade automatically gets thrown a tiny bit before it explodes, which means if you see a big shapeshifter you wish to take down, instead of hugging them, you should try to keep them a little bit in front of you.

However, if the spaceman/monster has a blast shield equipped, they can survive the explosion, leaving them with 10 HP instead (the monster in monster form always has an invisible blast shield).

In Survival mode and Story mode, all Frag Grenades found are replaced with Short-Fuse Frags, which can not be cooked and have a far shorter fuse than normal frags.