Extension Special Series No. 11H
The only way to be sure that a fire extinguisher will meet your needs is to have one that has the approval of the Underwriters' Laboratories and/or Factory Mutual. If the extinguisher is approved by either of these it will carry one of the labels shown below. This is your guarantee of quality.
South Dakota State University
Stevens, C. E. and Service, Cooperative Extension, "Selecting a Fire Extinguisher" (1970). SDSU Extension Special Series. 97.