The NumericIndicator provides the three following predefined styles (template prefixes): SevenSegs, HexagonalSevenSegs and FontFamily (it is used by default).
Currently template prefixes with name which start from the theme name (SummerSevenSegs, SummerHexagonalSevenSegs etc.) are not used. A predefined style is loaded from the current theme for the NumericIndicator control. The theme could be inherited form the RadGauge, a gauge scale and also you can use the telerik:StyleManager.Theme attribute directly in the NumericIndicator to specify the theme a predefined style will be used from.
the Telerik team