The Bendix+ TC-7 trailer control brake valve is a hand operated control valve that provides graduated control of service brake air pressure. The most common vehicle application is the independent control of the trailer's service brakes on a tractor-trailer combination. Typically, the TC-7 valve is mounted either inside the steering column or clamped to the exterior of the column. The three basic components of the TC-7 valve are available separately (valve, handle, bracket) to accommodate the appropriate mounting configuration. Because of its use as a trailer service brake control valve, the TC-7 valve should NOT be used in lieu of the vehicle parking brakes. The handle is marked NOT FOR PARKING. In general, the vehicle should not be left unattended when the TC-7 valve is in use.