2 Treble, 2 Bass. The Grover® “MINI” is lightweight, compact and durable for modern electric basses. Gear ratio is 20 to 1. Housing is specially machined to achieve the precise tolerance that prevents slippage and allows fine tuning. Sealed gear box has permanent lubrication that makes the MINI friction-free for life. Individually hand-tested. Screws and bushings included.