Upper Conn: Standard Double Banana Jack Material: Brass per QQ-B-626, Alloy 360, ½ Hard. Finish: Nickel plate per QQ-N-290, Class 2, (.00002/.0003). Insulation: ABS molded to Banana Jacks and Banana Plug Bodies. Color: Black. Marking: “POMONA 2952.” Lower Conn: Miniature Double Banana Plug Material: Spring – Beryllium Copper per QQ-C-533, Alloy 172, Cond. H.T. Plug Body: Same as above. Finish: Nickel plate per QQ-N-290.