An infection-preventing gastrostomy catheter kit to be used in the gastrostomy, which can pass an intragastric retainer of a catheter easily and reliably through an infection-preventing sheath by an easy maneuver, and which can reduce the diameter of the infection-preventing sheath. The equalization circuit includes a plurality of cascade-coupled delay taps. Herewith cross talk due to the intersection of the interconnections can be resolved. A blade case is positioned under the work surface including a first sidewall and an opposing second sidewall, and an air guide configured to channel the airflow into the blade case through an opening in the first sidewall. The back flap extension member adheres to the front flap extension member and portions of the front wall to close the second end. The device receives the transmitting audio signal addressed thereto through a communication interface, plays back the signal, and uses a speaker of the device to generate sound.