 In order to live in a CBR contaminated atmosphere, an individual must be able to put on his protective mask in 9 seconds or less. This demonstration will show you the techniques that you need to know for this accomplishment. This is the M17 protective mask. When it is issued to you, be sure it fits. Proper fitting prevents leakage between the face piece and the wearer's face and allows the mask to be worn comfortably. Combinations of different sizes of face planks and nose cups provide sufficient face piece sizes to properly fit all personnel. By trying them on, select a combination that will fit you. To fit the mask, loosen all head harness straps to within 1 inch of the clinch tips. Hold the voicemitter outlet valve assembly with one hand and press the face piece firmly against the face. Center the head harness pad on the back of the head and hold it in place with the other hand. Remove the hand from the voicemitter outlet valve assembly and tighten each of the forehead straps. Tighten just enough to remove the slack. Adjust the straps by rapid jerks rather than a steady pull. Adjust each cheek strap until both are moderately and evenly tightened. Remove the hand from the pad of the head harness. Using both hands, adjust the temple straps to a moderate tightness. If the straps are too tight or each matching pair are not equally tightened, they may cause discomfort or a leak may appear around the edge of the face piece. At this time, if the mask has been properly fitted, the pupils of your eyes will be near the centers of the lenses. Next, press the palms of the hands firmly over the inlet valve assemblies blocking the air inlets. Inhale normally. If the face piece collapses against the face, an effective airtight seal is indicated. If the face piece does not collapse, a leak is indicated and the straps should be readjusted. If the leak continues after adjustments to the straps, the mask should be exchanged. Once the M17 is properly fitted, you must learn to put it on as quickly as possible. Nine seconds is the maximum time that a trained soldier should require to don his protective mask. Before the soldier becomes that proficient, he must drill and drill and drill. In the preliminary training period, however, time is not a factor and commands are given in an informative manner. At the command gas, stop breathing immediately. During the informative command masking procedure, breathing may be resumed when necessary. Remove your headgear with the right hand and open the carrier with the left hand. Place the headgear as directed. Hold the carrier open with the left hand and grasp the face piece just below the eye pieces with the right hand. Remove the mask from the carrier. Grasp the face piece with both hands, sliding the thumbs up inside the face piece and under the lower head harness straps. Place the fingers straight and together on the outside of the face piece above the eye piece. Lift your chin slightly. At the command place, seat the chin pocket of the face piece firmly on the chin. Sweep the head harness smoothly over the head from front to rear. Make sure the head harness straps are straight and the head pad is centered on the back of the head. Smooth the edges of the face piece on the face with upward and backward motion of the hands. Press out all of the bulges to secure an airtight seal. At the command check, close the outlet valve by cupping the palm of the right hand firmly crosswise over the opening. Blow hard to clear the agent from the face piece. Use both hands to block the air inlet assemblies of the filter element. This will shut off the air supply. Inhale normally and hold it momentarily. No air should enter the mask and the face piece should remain collapsed. Normally, breathing would be resumed at this point. At the command cover, replace the headgear and fasten the carrier flap. At the command remove mask, remove the headgear with the left hand. With the right hand grasp the face piece by the voicemeter outlet valve assembly and remove the face piece with a circular motion, down, out, and up. Replace the headgear. With the left hand fold the head harness into the face piece. Then open the carrier with the left hand and start the mask into the carrier with the chin pocket forward and the eye pieces facing downward. At the command replace mask, insert the mask into the carrier. Tilt the mask upward so the face piece is facing out. Then close the carrier flap. After you become proficient in the mask drill, only the command's gas and remove and replace mask are used. Remember, at the command gas, stop breathing until you have donned and checked your mask. Gas, remove and replace mask. Remember, when you receive your protective mask, make sure it fits. Practice putting it on by using the mask drill. Remember that on the command gas, one, stop breathing. Two, remove headgear. Three, open carrier. Four, remove mask from carrier. On the command place, one, place mask on face. Two, smooth and center the head harness. Three, smooth face piece to secure an airtight fit. On the command check, one, clear mask. Two, check mask. Three, resume breathing. On the command cover, one, replace headgear. Two, close the carrier. On the command remove mask. One, raise headgear. Two, remove mask. Three, replace headgear. Four, fold head harness into the face piece. Five, open carrier. On the command replace, one, complete movement of replacing the mask. Two, fasten the carrier. It is important for every soldier to know how to properly fit the M17 protective mask to his face and to fully understand correct masking procedures. Your knowledge and skill in donning the mask quickly will save your life in the event of a chemical and biological attack.