I use mine... it's Magnum Mini Tach designed for 2 or 3 blade props. I bought mine for $24.99 and I use it all the time do to I always experiment with different prop sizes and pitch. It's also good to have if you down the road want to fly twins, you can sync the engines better. Also with a tach, you can keep tabs on how hard your engine is working. I also have a Radio Shack IR Thermometer to know how hot my engine is in those " In Cowel " setups. But that's a different topic. [X(]