... ), extense adaptor, extension nipples, reduction nipples; Description: Reducer adaptors (single fitting, brass coupler), extense adaptor, extension nipples, reduction nipples; Thread type ... : BSP or NPT, parallel or taper; Optional materials: Brass or steel;Surface treatment: Acid washing, galvanize;Optional thread sizes ... /8", 1/4", 3/8", 1/2", 3/4"; Reducer Adaptor (Single Fitting, Brass Coupler)