Abstract: The present disclosure provides a gas sensor. The gas sensor includes a substrate, a conductor layer over the substrate, wherein the conductor layer includes a conductive pattern including a plurality of openings, the openings being arranged in a repeating pattern, an insulating layer in the plurality of openings and over a top surface of the conductive pattern, wherein the conductive pattern is embedded in the insulating layer, and a gas sensing film over a portion of the insulating layer.

Abstract: A scooter includes a wheel rotatably secured to a board, a spring engaged in one end of the mudguard, and a shaft engaged through the mudguard and the spring for easily and quickly securing the mudguard and the spring to the board. The spring may bias the mudguard away from the wheel. The mudguard includes a bulge extended from the inner peripheral surface for engaging with the wheel and for decreasing the contacting area of the mudguard with the wheel. The spring has two coils engaged on the shaft, and a connected middle portion for increasing the resilience of the spring.