Can I find old gas masks from WW2?

Try filling your water reservoir a little less. Unfortunately there really is no real fix for this. Mine does the same thing. And if you don't put water in you will wake up with a very dry throat

where are you located? & are you looking for one to cook on or collectible vintage ones?
where i live in Paterson,nj,we have stores that sell used stoves/refrigerators,etc,restored to almost new condition,for about $150.-maybe there's some of these businesses near you?
my friend is selling a vintage stove,but unless you are local & can pick it up, i can imagine the shipping charges to get it to you would equal buying a top of the line stove in your area.

This is a modern compass. WW2 compass are made of brass and will be stamped with a broad arrow mark. Non of the WW2 compasses in my collection have a mirror.

The gas mask is a mask used to protect the user from inhaling airborne pollutants and toxic gasses. The mask forms a sealed cover over the nose and mouth, but may also cover the eyes and other vulnerable soft tissues of the face. Some gas masks are also respirators, though the word gas mask is often used to refer to military equipment (e.g. field protective mask). The user of the gas mask is not protected from gas that the skin can absorb. Most gas mask filters will last around 24 hours in a nuclear biological chemical (NBC) situation.
Airborne toxic materials may be gaseous (for example sulfur mustard and chlorine gas used in World War I) or particulates (such as many biological agents developed for weapons such as bacteria, viruses, and toxins). Many gas masks include protection from both types. Gas masks are used in construction to protect against welding fumes, in deconstruction to protect against asbestos or other hazardous particles, and in the chemical industry when handling hazardous materials, as in making repairs to leaking equipment or cleaning up after spills; workers have usually issued gas masks as a precaution against leaks.
During demonstrations and protests where tear gas or CS-gas is employed by riot police, gas masks are commonly used by police and demonstrators alike. Aside from serving their functional purposes, gas masks are also used as emblems in industrial music, with the most notable example, the subgenre of drum and bass called Neurofunk. These emblems are used by graffiti taggers because the mask protects them from the paint canister's toxic fumes, and by urban explorers venturing into environments where hazardous materials, such as asbestos, may be present.

I found this site - The National Terror Alert Response Center - it looks like it's run by Homeland Security. They have an article about obsolete gas mask models you should avoid that you can find here: http://www.nationalterroralert.com/gasmasks/
They also have lots of preparedness guides that you can access on the site.

If it's the Gypsy Camp:

Objectives:

Protect Keim Bey.
Get The Sniper Rifle.
Rescue 4 Hostages.
Defeat The Gunner.

Awards:

30 Disables.......You have to take down 30 enemies via any method.
9 Minutes.........You have to complete the mission in 9 minutes.
Bond Moment.......You have to find a way into the kitchen.
Difficulty........You have to play with 00 Agent difficulty.

Schematics: 4 Available

Your first objective is to take out the gunner of the turrect, try to clear
the mess a little before locking onto the turret, then just keep shooting at
it until it's health metre dops to zero. Head left and take the gasmask by
the wagon. Now go behind the wagon and kill two enemies and enter through an
opening, take out another enemy to free 1/4 hostages. After you get the
gas mask, go to the building highlighted in the cut-scene, towards the right
of the wagon with the gas mask equipped. Enter the door and take out two
guards and collect everything on this floor. If your gas mask metre finishes,
come outside and get another one, go back to this building and kill two
guards on the upper floor to free 2/4 hostages.

In this building, stay on the upper floor and take out a Q-copter.

Q-Copter Controls:

Left Analog Stick......Navigation
Right Analog Stick.....Left/Right Navigation
X Button........Ascend
SQUARE Button.......Descend
R1 Button.....Self Destructing Explosion

Navigate it downstairs. There should be a small opening underneath the
stairway, navigate it through it into the kitchen and blast it near the chair.
Now go back down and enter the kitchen. Take out the guard and collect
everything. Comeback outside. As you comeout of the door, head right and
then behind the building. You will see another door, make sure you are wearing
a gas mask and then go through the door, take out some guards to rescue
3/4 hostages.

Replenish your gas mask and go towards the rappel point near the buggy. Go
up. Follow the path downstairs and kill the guard to rescue 4/4 hostages.
Cut-scene. Go towards the buggy placed directly infront of the rappel and
enter the door nearby. Rappel up. Collect the sniper rounds and move forward
taking down the enemy below. Jump the gap and collect the sniper rifle. Now
go towards the place where you got the sniper rounds and stay there because
they regenerate. Take down as many enemies as you can until the stage ends.
If you find the sniper rifle difficult to handle then use your other weapons
because they also do the job perfectly fine.

*from Gamesfaqs, a_heavenly_body

You first enter your inventory, and then you should be able to equip it whenever you need.

There is a reason for the difference in price, one is purely for surface observation and the other is able to stand the pressures of deeper water diving... If your going to scuba dive the investment is worth it, don't skimp on safety…