The 7.2V Scarlett Smoke unit has a secondary fan, and is fully proportional WITH NO SOLDERING REQUIRED It is designed to work with Heng Long V5.2 and V5.3, Tamiya, Torro, and other radio controlled 7.2V tanks with one or two motors. The G.I. Tank Smokers are available in 4 different models to upgrade to a quieter, more reliable and more realistic smoke effect for your RC tank. The unit features metal construction, fitted with a guarded brushless fan for quiet operation, low power consumption of around 1 AMP, and extended run time of over 2 hours on one full fill up of Fluid. They come in a very compact size of approximately 2 1/4” L (5.7 CM), (2 1/2” L (6.35 CM) including the side brass fitting) 1-5/8” W (4 CM), 1-1/2” (3.8 CM) (1-7/8” H (4.8 CM) for the Scarlett) without tubing/wiring, and a weight of just over 3 OZ (85 Grams) when filled with fluid. An optional "Smoking Barrel" kit and instructions are also included for tanks equipped with an air soft mechanism. Not for use with IR. Each unit comes with tubing, directions and a wiring diagram. A Sample bottle of fluid is also included for shipments to the Continental United States.