Abstract: A gage construction having a casing body provided with a generally circular front face interconnected to a rear mounting flange by an annular side wall disposed therebetween and which generally increases radially outwardly from the front wall to the rear mounting flange, the side wall having a generally polygonal exterior surface portion adjacent the rear mounting flange and a generally frusto-conical exterior surface portion adjacent the front face. The surface portions blend together between the front face and the rear mounting flange.