Katorisenkō (蚊取線香, 蚊取り線香): a coil of insect-repellent incense originally made from pyrethrum, a chrysanthemum with insecticidal properties. Invented in 1902 in Japan. Often placed in a ceramic kayari buta.
Along with wind chimes, paper fans, sitting on the porch (endai), etc, commonly included in domestic summer scenes.