A-A-2160 Hose Assembly, Nonmetallic (Booster) (S/S By Nfpa-1964)This description covers booster hoses, double braided, rubber covered, with coupling for both fire protection and general purposes and shall be furnished in the following classes and sizes, as specified: Class I - 800 psf (working pressure) Class II - 400 psf (working pressure) Class III - 300 psf (working pressure) Size A - 3/4 inch Size B - 1 inch.