Plant backflow incense cones - citronella & lemongrass stamford premium plant based backflow incense cones with a higher fragrance percentage giving a more intense long-lasting aroma when in use. - hand rolled top quality incense - approximate burn time: 30 minutes - cruelty free, vegan material : resins and plant material when their tip is lighted, the smoke flows down the incense burner like a waterfall, creating an unusual and beautiful effect. please note that these cones are only for use with back flow incense burners.