Canister-holding housing of emergency mask
FIG. 1 is a perspective view of the canister-holding housing of emergency mask; 
     FIG. 2 is a front elevation view thereof; 
     FIG. 3 is a rear elevation view thereof; 
     FIG. 4 is a top plan view thereof; 
     FIG. 5 is a bottom plan view thereof; 
     FIG. 6 is a right side elevation view thereof; 
     FIG. 7 is a cross-sectional view thereof, taken along the line 7--7 of FIG. 2.