This is Yeah Racing Performance Motor Brush. Motor brushes wear out over time resulting in decreased motor performance. Spraying out the motor with motor cleaner and installing new brushes can help maintain the performance of a brushed motor. Yeah Racing exquisitely use the premium quality of compound for this product. Compound is carefully formulated to achieve both great performance and durability. Also these brushes used the heat treatment in the production process. These brushes is also sintered for its optimal performance. These brushes are intended to use with high quality brushed motor such as Hackmoto v2.