A gyroscopic safety sensor on Wacker 's CT Series walk-behind trowels provides operator protection. After the operator looses hold of the handle, it will begin to spin counterclockwise. The sensor then stops the engine and engages the gearbox brake. Momentum will carry the handle, but it will stop within a 270-degree rotation. To eliminate runaway handle rotation during restarts, the engine rev-limiter senses engine acceleration during starting and will not let the operator start the machine at full throttle. To reduce operator fatigue, Wacker has moved the engine to center the weight of the trowel. Estimated list price: $2,200 to $3,000.