Please ask any and all questions before purchasing!Bass KnobThe Bass Control is a remote volume control for amplifiers. Its main purpose is to control Subwoofer volume in a practical way and in real time, as it can be fixed on the vehicle’s dashboard for easy access. With RCA audio inputs and outputs, it can be used with all models of head units and amplifiers with this type of connection. This is Taramps putting you in control.TS 400X4 HIGH LEVEL INPUTWe know that the demand for amplifiers that are compatible with original players has been growing every day. With that in mind, we created a version of the TS 4004 that has a high input with automatic activation. This makes the use of adapters unnecessary, which is ideal for this type of application.