A light emitting device includes a light emitting element, a base, and a transparent layer. In the context of a biped, the structure is used for a pair of hind limbs. The outer member can be secured with respect to other portions of the housing for the electronic device. The ultrasonic dental scaler also supports two footswitches. The pilot fuel circuit is in close proximity to the main fuel circuit enroute to the pilot fuel atomizer so that the pilot fuel flow cools stagnant fuel located within the main fuel circuit during low engine power operation to prevent coking. Features for emergency bypass and external power supplies are included.