There is provided a method for producing a succinimide compound. The integrated, detachable ear bud system may be one ear bud, or pair of ear buds, or ear bud or ear buds including a microphone. The plunger machine used in the method includes a barrel housing with a smooth walled barrel with longitudinal fins projecting inwardly towards the center of the bore that defines a main melt chamber. , greater than zero but less than 10 weight percent tin and greater than 90 but less than 100 weight percent zinc improve the chemical durability of a high transmittance, low emissivity coating stack over coating stacks having zinc oxides without tin oxide.