Reverse Parking Systems - 4 Sensor Stick-On Style 4 Sensor Stick-On Style (91CMD05-4SO) "The CMDO5 series Command Systems are an exceptional quality product, at an affordable entry level price. The CMDO5 series features a variable stage audible buzzer which can provide an early warning of obstacles behind your vehicle. This series is available in a 2 sensor configuration, or 4 sensor configuration for extra ultrasonic coverage. All models now include premium sensors. The series has expanded to include stick on sensors that do not require drilling into a rear bumper. These products are perfect for those who want the protection of reversing sensors on vehicles without drilling and at value for money prices. (Stick on)"