The Regin S220 Smoke Pen produces cool, dense smoke--perfect for finding air leaks around windows, doors, chimneys, exhaust hoods and laboratory equipment. Ideal for air balancing, verifying ventilation systems, and verifying negative or positive air pressure. A handy tool for K9 scent detection training. Also great for testing smoke alarms. The smoke stream is dense and white, reacting readily to small drafts and light air movement. The smoke has great hang time, letting you watch air flow patterns over long distances. The S220 Smoke Pen contains a patented smoke-emitting wick that is lit with a cigarette lighter or match. The glowing tip emits smoke for as long as you need. A single wick will emit smoke for up to half hour, but can be start and stopped by capping and relighting as needed. There is no waste, no mess—, only safe non-toxic smoke. The unused portion of the wick stores safely in the barrel of the pen. The reusable Smoke Pen comes with six wicks, providing a total of three hours of continuous smoke or about 360 individual 30-second tests. The S220 Smoke Pen has a long shelf life when stored in a cool dry location. Order S221 refill wicks separately