The OKY3321 is a 5VDC MQ-2 sensor manufactured by OKYSTAR, designed to measure combustible gases. The device is small, consisting of a sensing element, a burn-in board and a heater. It is sensitive to a variety of combustible gases, such as methane (CH4), propane (C3H8), and alcohol (C2H5OH). The device also has an automatic compensation temperature range, an adjustable temperature compensation level, and a low temperature drift. It is a durable, robust, and reliable product with a long lifetime.