Like a watch or thermometer, the C1LinearGauge control includes a C1Gauge.Face and a  C1Gauge.Cover. The C1Gauge.Face appears above the background but behind the pointer and other decorators, and the C1Gauge.Cover appears, like a glass over a thermometer, above all other elements. For example, in the image below the C1Gauge.Face includes a gradient that appears behind the elements in the gauge and the C1Gauge.Cover includes text that appears above the C1Gauge.Face and all other elements:

You can customize the appearance of the C1Gauge.Cover by using the C1Gauge.CoverTemplate and you can customize the appearance of the C1Gauge.Face by using the C1Gauge.FaceTemplate.