I cannot find Specular Render Element

Corona Renderer, as opposed to other rendering engines, does not support fake specular reflections. The visual appearance of a reflection is determined by the object's material's settings and its environment. The CESSENTIAL_Reflect render element includes scene reflections and reflections from direct light sources. If needed, those can be divided into two separate passes using the CShading_Components render element.

For a complete list of render elements, see: What available render elements are there?