2 in. camlock type B PP Coupler Female Coupler x Male NPT Thread Black Polypropylene Camlock Fitting. The Type B coupler is ordinarily used with a Type F adapter. However, this Type B coupler can be used with a Type A or E adapter as well as a DP (Dust Plug) of matching size. Type B Coupler – Polypropylene Cam and Groove Female Coupler x Male NPT Thread.