The Grayhill 62C is a concentric shaft encoder. Two concentric shafts in one package allow additional functionality while conserving space and weight. Grayhill also offers the 62N, a concentric shaft encoder in which the inside shaft does not rotate but does contain the pushbutton feature. This is required when the pushbutton feature needs to be on a different shaft to prevent accidental actuation. The non turn shaft also insures that any legends printed on the knob stay in their proper orientation. Applications for these products include avionics and medical devices.