These decoders feature MRC's versatile back EMF feature that uses enhanced feedback circuitry to instantly adjusts the motor's speed feedback. Air compressor, blower and other sounds can be manually activated on or off. The air compressor sound is synched with the RPM of the prime mover. Applying the brake sound will slow the loco down and activate the brake squeal. Activating the dynamic brake feature provides sound and slows down the loco. Seventeen different lighting controls include gyro lights, ditch lights, Mars lights, strobe, oscillating headlight, cabin and more.